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# Guan is an open-source python package developed and maintained by https://www.guanjihuan.com/about. The primary location of this package is on website https://py.guanjihuan.com.
# Modules
# # Module 1: basic functions
# # Module 2: Fourier transform
# # Module 3: Hamiltonian of finite size systems
# # Module 4: Hamiltonian of models in the reciprocal space
# # Module 5: band structures and wave functions
# # Module 6: Green functions
# # Module 7: density of states
# # Module 8: quantum transport
# # Module 9: topological invariant
# # Module 10: read and write
# # Module 11: plot figures
# # Module 12: data processing
# # Module 13: others
# import packages
import numpy as np
from math import *
import cmath
import copy
import guan
# Module 1: basic functions
## test
def test():
print('\nSuccess in the installation of Guan package!\n')
## Pauli matrices
def sigma_0():
return np.eye(2)
def sigma_x():
return np.array([[0, 1],[1, 0]])
def sigma_y():
return np.array([[0, -1j],[1j, 0]])
def sigma_z():
return np.array([[1, 0],[0, -1]])
## Kronecker product of Pauli matrices
def sigma_00():
return np.kron(sigma_0(), sigma_0())
def sigma_0x():
return np.kron(sigma_0(), sigma_x())
def sigma_0y():
return np.kron(sigma_0(), sigma_y())
def sigma_0z():
return np.kron(sigma_0(), sigma_z())
def sigma_x0():
return np.kron(sigma_x(), sigma_0())
def sigma_xx():
return np.kron(sigma_x(), sigma_x())
def sigma_xy():
return np.kron(sigma_x(), sigma_y())
def sigma_xz():
return np.kron(sigma_x(), sigma_z())
def sigma_y0():
return np.kron(sigma_y(), sigma_0())
def sigma_yx():
return np.kron(sigma_y(), sigma_x())
def sigma_yy():
return np.kron(sigma_y(), sigma_y())
def sigma_yz():
return np.kron(sigma_y(), sigma_z())
def sigma_z0():
return np.kron(sigma_z(), sigma_0())
def sigma_zx():
return np.kron(sigma_z(), sigma_x())
def sigma_zy():
return np.kron(sigma_z(), sigma_y())
def sigma_zz():
return np.kron(sigma_z(), sigma_z())
# Module 2: Fourier_transform
# Fourier transform for discrete lattices
def one_dimensional_fourier_transform(k, unit_cell, hopping):
unit_cell = np.array(unit_cell)
hopping = np.array(hopping)
hamiltonian = unit_cell+hopping*cmath.exp(1j*k)+hopping.transpose().conj()*cmath.exp(-1j*k)
return hamiltonian
def two_dimensional_fourier_transform_for_square_lattice(k1, k2, unit_cell, hopping_1, hopping_2):
unit_cell = np.array(unit_cell)
hopping_1 = np.array(hopping_1)
hopping_2 = np.array(hopping_2)
hamiltonian = unit_cell+hopping_1*cmath.exp(1j*k1)+hopping_1.transpose().conj()*cmath.exp(-1j*k1)+hopping_2*cmath.exp(1j*k2)+hopping_2.transpose().conj()*cmath.exp(-1j*k2)
return hamiltonian
def three_dimensional_fourier_transform_for_cubic_lattice(k1, k2, k3, unit_cell, hopping_1, hopping_2, hopping_3):
unit_cell = np.array(unit_cell)
hopping_1 = np.array(hopping_1)
hopping_2 = np.array(hopping_2)
hopping_3 = np.array(hopping_3)
hamiltonian = unit_cell+hopping_1*cmath.exp(1j*k1)+hopping_1.transpose().conj()*cmath.exp(-1j*k1)+hopping_2*cmath.exp(1j*k2)+hopping_2.transpose().conj()*cmath.exp(-1j*k2)+hopping_3*cmath.exp(1j*k3)+hopping_3.transpose().conj()*cmath.exp(-1j*k3)
return hamiltonian
def one_dimensional_fourier_transform_with_k(unit_cell, hopping):
import functools
hamiltonian_function = functools.partial(guan.one_dimensional_fourier_transform, unit_cell=unit_cell, hopping=hopping)
return hamiltonian_function
def two_dimensional_fourier_transform_for_square_lattice_with_k1_k2(unit_cell, hopping_1, hopping_2):
import functools
hamiltonian_function = functools.partial(guan.two_dimensional_fourier_transform_for_square_lattice, unit_cell=unit_cell, hopping_1=hopping_1, hopping_2=hopping_2)
return hamiltonian_function
def three_dimensional_fourier_transform_for_cubic_lattice_with_k1_k2_k3(unit_cell, hopping_1, hopping_2, hopping_3):
import functools
hamiltonian_function = functools.partial(guan.three_dimensional_fourier_transform_for_cubic_lattice, unit_cell=unit_cell, hopping_1=hopping_1, hopping_2=hopping_2, hopping_3=hopping_3)
return hamiltonian_function
## calculate reciprocal lattice vectors
def calculate_one_dimensional_reciprocal_lattice_vector(a1):
b1 = 2*np.pi/a1
return b1
def calculate_two_dimensional_reciprocal_lattice_vectors(a1, a2):
a1 = np.array(a1)
a2 = np.array(a2)
a1 = np.append(a1, 0)
a2 = np.append(a2, 0)
a3 = np.array([0, 0, 1])
b1 = 2*np.pi*np.cross(a2, a3)/np.dot(a1, np.cross(a2, a3))
b2 = 2*np.pi*np.cross(a3, a1)/np.dot(a1, np.cross(a2, a3))
b1 = np.delete(b1, 2)
b2 = np.delete(b2, 2)
return b1, b2
def calculate_three_dimensional_reciprocal_lattice_vectors(a1, a2, a3):
a1 = np.array(a1)
a2 = np.array(a2)
a3 = np.array(a3)
b1 = 2*np.pi*np.cross(a2, a3)/np.dot(a1, np.cross(a2, a3))
b2 = 2*np.pi*np.cross(a3, a1)/np.dot(a1, np.cross(a2, a3))
b3 = 2*np.pi*np.cross(a1, a2)/np.dot(a1, np.cross(a2, a3))
return b1, b2, b3
def calculate_one_dimensional_reciprocal_lattice_vector_with_sympy(a1):
import sympy
b1 = 2*sympy.pi/a1
return b1
def calculate_two_dimensional_reciprocal_lattice_vectors_with_sympy(a1, a2):
import sympy
a1 = sympy.Matrix(1, 3, [a1[0], a1[1], 0])
a2 = sympy.Matrix(1, 3, [a2[0], a2[1], 0])
a3 = sympy.Matrix(1, 3, [0, 0, 1])
cross_a2_a3 = a2.cross(a3)
cross_a3_a1 = a3.cross(a1)
b1 = 2*sympy.pi*cross_a2_a3/a1.dot(cross_a2_a3)
b2 = 2*sympy.pi*cross_a3_a1/a1.dot(cross_a2_a3)
b1 = sympy.Matrix(1, 2, [b1[0], b1[1]])
b2 = sympy.Matrix(1, 2, [b2[0], b2[1]])
return b1, b2
def calculate_three_dimensional_reciprocal_lattice_vectors_with_sympy(a1, a2, a3):
import sympy
cross_a2_a3 = a2.cross(a3)
cross_a3_a1 = a3.cross(a1)
cross_a1_a2 = a1.cross(a2)
b1 = 2*sympy.pi*cross_a2_a3/a1.dot(cross_a2_a3)
b2 = 2*sympy.pi*cross_a3_a1/a1.dot(cross_a2_a3)
b3 = 2*sympy.pi*cross_a1_a2/a1.dot(cross_a2_a3)
return b1, b2, b3
# Module 3: Hamiltonian of finite size systems
def hamiltonian_of_finite_size_system_along_one_direction(N, on_site=0, hopping=1, period=0):
on_site = np.array(on_site)
hopping = np.array(hopping)
if on_site.shape==():
dim = 1
else:
dim = on_site.shape[0]
hamiltonian = np.zeros((N*dim, N*dim), dtype=complex)
for i0 in range(N):
hamiltonian[i0*dim+0:i0*dim+dim, i0*dim+0:i0*dim+dim] = on_site
for i0 in range(N-1):
hamiltonian[i0*dim+0:i0*dim+dim, (i0+1)*dim+0:(i0+1)*dim+dim] = hopping
hamiltonian[(i0+1)*dim+0:(i0+1)*dim+dim, i0*dim+0:i0*dim+dim] = hopping.transpose().conj()
if period == 1:
hamiltonian[(N-1)*dim+0:(N-1)*dim+dim, 0:dim] = hopping
hamiltonian[0:dim, (N-1)*dim+0:(N-1)*dim+dim] = hopping.transpose().conj()
return hamiltonian
def hamiltonian_of_finite_size_system_along_two_directions_for_square_lattice(N1, N2, on_site=0, hopping_1=1, hopping_2=1, period_1=0, period_2=0):
on_site = np.array(on_site)
hopping_1 = np.array(hopping_1)
hopping_2 = np.array(hopping_2)
if on_site.shape==():
dim = 1
else:
dim = on_site.shape[0]
hamiltonian = np.zeros((N1*N2*dim, N1*N2*dim), dtype=complex)
for i1 in range(N1):
for i2 in range(N2):
hamiltonian[i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim, i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim] = on_site
for i1 in range(N1-1):
for i2 in range(N2):
hamiltonian[i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim, (i1+1)*N2*dim+i2*dim+0:(i1+1)*N2*dim+i2*dim+dim] = hopping_1
hamiltonian[(i1+1)*N2*dim+i2*dim+0:(i1+1)*N2*dim+i2*dim+dim, i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim] = hopping_1.transpose().conj()
for i1 in range(N1):
for i2 in range(N2-1):
hamiltonian[i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim, i1*N2*dim+(i2+1)*dim+0:i1*N2*dim+(i2+1)*dim+dim] = hopping_2
hamiltonian[i1*N2*dim+(i2+1)*dim+0:i1*N2*dim+(i2+1)*dim+dim, i1*N2*dim+i2*dim+0:i1*N2*dim+i2*dim+dim] = hopping_2.transpose().conj()
if period_1 == 1:
for i2 in range(N2):
hamiltonian[(N1-1)*N2*dim+i2*dim+0:(N1-1)*N2*dim+i2*dim+dim, i2*dim+0:i2*dim+dim] = hopping_1
hamiltonian[i2*dim+0:i2*dim+dim, (N1-1)*N2*dim+i2*dim+0:(N1-1)*N2*dim+i2*dim+dim] = hopping_1.transpose().conj()
if period_2 == 1:
for i1 in range(N1):
hamiltonian[i1*N2*dim+(N2-1)*dim+0:i1*N2*dim+(N2-1)*dim+dim, i1*N2*dim+0:i1*N2*dim+dim] = hopping_2
hamiltonian[i1*N2*dim+0:i1*N2*dim+dim, i1*N2*dim+(N2-1)*dim+0:i1*N2*dim+(N2-1)*dim+dim] = hopping_2.transpose().conj()
return hamiltonian
def hamiltonian_of_finite_size_system_along_three_directions_for_cubic_lattice(N1, N2, N3, on_site=0, hopping_1=1, hopping_2=1, hopping_3=1, period_1=0, period_2=0, period_3=0):
on_site = np.array(on_site)
hopping_1 = np.array(hopping_1)
hopping_2 = np.array(hopping_2)
hopping_3 = np.array(hopping_3)
if on_site.shape==():
dim = 1
else:
dim = on_site.shape[0]
hamiltonian = np.zeros((N1*N2*N3*dim, N1*N2*N3*dim), dtype=complex)
for i1 in range(N1):
for i2 in range(N2):
for i3 in range(N3):
hamiltonian[i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim, i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim] = on_site
for i1 in range(N1-1):
for i2 in range(N2):
for i3 in range(N3):
hamiltonian[i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim, (i1+1)*N2*N3*dim+i2*N3*dim+i3*dim+0:(i1+1)*N2*N3*dim+i2*N3*dim+i3*dim+dim] = hopping_1
hamiltonian[(i1+1)*N2*N3*dim+i2*N3*dim+i3*dim+0:(i1+1)*N2*N3*dim+i2*N3*dim+i3*dim+dim, i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim] = hopping_1.transpose().conj()
for i1 in range(N1):
for i2 in range(N2-1):
for i3 in range(N3):
hamiltonian[i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim, i1*N2*N3*dim+(i2+1)*N3*dim+i3*dim+0:i1*N2*N3*dim+(i2+1)*N3*dim+i3*dim+dim] = hopping_2
hamiltonian[i1*N2*N3*dim+(i2+1)*N3*dim+i3*dim+0:i1*N2*N3*dim+(i2+1)*N3*dim+i3*dim+dim, i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim] = hopping_2.transpose().conj()
for i1 in range(N1):
for i2 in range(N2):
for i3 in range(N3-1):
hamiltonian[i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim, i1*N2*N3*dim+i2*N3*dim+(i3+1)*dim+0:i1*N2*N3*dim+i2*N3*dim+(i3+1)*dim+dim] = hopping_3
hamiltonian[i1*N2*N3*dim+i2*N3*dim+(i3+1)*dim+0:i1*N2*N3*dim+i2*N3*dim+(i3+1)*dim+dim, i1*N2*N3*dim+i2*N3*dim+i3*dim+0:i1*N2*N3*dim+i2*N3*dim+i3*dim+dim] = hopping_3.transpose().conj()
if period_1 == 1:
for i2 in range(N2):
for i3 in range(N3):
hamiltonian[(N1-1)*N2*N3*dim+i2*N3*dim+i3*dim+0:(N1-1)*N2*N3*dim+i2*N3*dim+i3*dim+dim, i2*N3*dim+i3*dim+0:i2*N3*dim+i3*dim+dim] = hopping_1
hamiltonian[i2*N3*dim+i3*dim+0:i2*N3*dim+i3*dim+dim, (N1-1)*N2*N3*dim+i2*N3*dim+i3*dim+0:(N1-1)*N2*N3*dim+i2*N3*dim+i3*dim+dim] = hopping_1.transpose().conj()
if period_2 == 1:
for i1 in range(N1):
for i3 in range(N3):
hamiltonian[i1*N2*N3*dim+(N2-1)*N3*dim+i3*dim+0:i1*N2*N3*dim+(N2-1)*N3*dim+i3*dim+dim, i1*N2*N3*dim+i3*dim+0:i1*N2*N3*dim+i3*dim+dim] = hopping_2
hamiltonian[i1*N2*N3*dim+i3*dim+0:i1*N2*N3*dim+i3*dim+dim, i1*N2*N3*dim+(N2-1)*N3*dim+i3*dim+0:i1*N2*N3*dim+(N2-1)*N3*dim+i3*dim+dim] = hopping_2.transpose().conj()
if period_3 == 1:
for i1 in range(N1):
for i2 in range(N2):
hamiltonian[i1*N2*N3*dim+i2*N3*dim+(N3-1)*dim+0:i1*N2*N3*dim+i2*N3*dim+(N3-1)*dim+dim, i1*N2*N3*dim+i2*N3*dim+0:i1*N2*N3*dim+i2*N3*dim+dim] = hopping_3
hamiltonian[i1*N2*N3*dim+i2*N3*dim+0:i1*N2*N3*dim+i2*N3*dim+dim, i1*N2*N3*dim+i2*N3*dim+(N3-1)*dim+0:i1*N2*N3*dim+i2*N3*dim+(N3-1)*dim+dim] = hopping_3.transpose().conj()
return hamiltonian
def hopping_matrix_along_zigzag_direction_for_graphene_ribbon(N):
hopping = np.zeros((4*N, 4*N), dtype=complex)
for i0 in range(N):
hopping[4*i0+1, 4*i0+0] = 1
hopping[4*i0+2, 4*i0+3] = 1
return hopping
def hamiltonian_of_finite_size_system_along_two_directions_for_graphene(N1, N2, period_1=0, period_2=0):
on_site = guan.hamiltonian_of_finite_size_system_along_one_direction(4)
hopping_1 = guan.hopping_matrix_along_zigzag_direction_for_graphene_ribbon(1)
hopping_2 = np.zeros((4, 4), dtype=complex)
hopping_2[3, 0] = 1
hamiltonian = guan.finite_size_along_two_directions_for_square_lattice(N1, N2, on_site, hopping_1, hopping_2, period_1, period_2)
return hamiltonian
# Module 4: Hamiltonian of models in the reciprocal space
def hamiltonian_of_simple_chain(k):
hamiltonian = guan.one_dimensional_fourier_transform(k, unit_cell=0, hopping=1)
return hamiltonian
def hamiltonian_of_square_lattice(k1, k2):
hamiltonian = guan.two_dimensional_fourier_transform_for_square_lattice(k1, k2, unit_cell=0, hopping_1=1, hopping_2=1)
return hamiltonian
def hamiltonian_of_square_lattice_in_quasi_one_dimension(k, N=10):
h00 = np.zeros((N, N), dtype=complex) # hopping in a unit cell
h01 = np.zeros((N, N), dtype=complex) # hopping between unit cells
for i in range(N-1):
h00[i, i+1] = 1
h00[i+1, i] = 1
for i in range(N):
h01[i, i] = 1
hamiltonian = guan.one_dimensional_fourier_transform(k, unit_cell=h00, hopping=h01)
return hamiltonian
def hamiltonian_of_cubic_lattice(k1, k2, k3):
hamiltonian = guan.three_dimensional_fourier_transform_for_cubic_lattice(k1, k2, k3, unit_cell=0, hopping_1=1, hopping_2=1, hopping_3=1)
return hamiltonian
def hamiltonian_of_ssh_model(k, v=0.6, w=1):
hamiltonian = np.zeros((2, 2), dtype=complex)
hamiltonian[0,1] = v+w*cmath.exp(-1j*k)
hamiltonian[1,0] = v+w*cmath.exp(1j*k)
return hamiltonian
def hamiltonian_of_graphene(k1, k2, M=0, t=1, a=1/sqrt(3)):
h0 = np.zeros((2, 2), dtype=complex) # mass term
h1 = np.zeros((2, 2), dtype=complex) # nearest hopping
h0[0, 0] = M
h0[1, 1] = -M
h1[1, 0] = t*(cmath.exp(1j*k2*a)+cmath.exp(1j*sqrt(3)/2*k1*a-1j/2*k2*a)+cmath.exp(-1j*sqrt(3)/2*k1*a-1j/2*k2*a))
h1[0, 1] = h1[1, 0].conj()
hamiltonian = h0 + h1
return hamiltonian
def hamiltonian_of_graphene_with_zigzag_in_quasi_one_dimension(k, N=10, M=0, t=1):
h00 = np.zeros((4*N, 4*N), dtype=complex) # hopping in a unit cell
h01 = np.zeros((4*N, 4*N), dtype=complex) # hopping between unit cells
for i in range(N):
h00[i*4+0, i*4+0] = M
h00[i*4+1, i*4+1] = -M
h00[i*4+2, i*4+2] = M
h00[i*4+3, i*4+3] = -M
h00[i*4+0, i*4+1] = t
h00[i*4+1, i*4+0] = t
h00[i*4+1, i*4+2] = t
h00[i*4+2, i*4+1] = t
h00[i*4+2, i*4+3] = t
h00[i*4+3, i*4+2] = t
for i in range(N-1):
h00[i*4+3, (i+1)*4+0] = t
h00[(i+1)*4+0, i*4+3] = t
for i in range(N):
h01[i*4+1, i*4+0] = t
h01[i*4+2, i*4+3] = t
hamiltonian = guan.one_dimensional_fourier_transform(k, unit_cell=h00, hopping=h01)
return hamiltonian
def hamiltonian_of_haldane_model(k1, k2, M=2/3, t1=1, t2=1/3, phi=pi/4, a=1/sqrt(3)):
h0 = np.zeros((2, 2), dtype=complex) # mass term
h1 = np.zeros((2, 2), dtype=complex) # nearest hopping
h2 = np.zeros((2, 2), dtype=complex) # next nearest hopping
h0[0, 0] = M
h0[1, 1] = -M
h1[1, 0] = t1*(cmath.exp(1j*k2*a)+cmath.exp(1j*sqrt(3)/2*k1*a-1j/2*k2*a)+cmath.exp(-1j*sqrt(3)/2*k1*a-1j/2*k2*a))
h1[0, 1] = h1[1, 0].conj()
h2[0, 0] = t2*cmath.exp(-1j*phi)*(cmath.exp(1j*sqrt(3)*k1*a)+cmath.exp(-1j*sqrt(3)/2*k1*a+1j*3/2*k2*a)+cmath.exp(-1j*sqrt(3)/2*k1*a-1j*3/2*k2*a))
h2[1, 1] = t2*cmath.exp(1j*phi)*(cmath.exp(1j*sqrt(3)*k1*a)+cmath.exp(-1j*sqrt(3)/2*k1*a+1j*3/2*k2*a)+cmath.exp(-1j*sqrt(3)/2*k1*a-1j*3/2*k2*a))
hamiltonian = h0 + h1 + h2 + h2.transpose().conj()
return hamiltonian
def hamiltonian_of_haldane_model_in_quasi_one_dimension(k, N=10, M=2/3, t1=1, t2=1/3, phi=pi/4):
h00 = np.zeros((4*N, 4*N), dtype=complex) # hopping in a unit cell
h01 = np.zeros((4*N, 4*N), dtype=complex) # hopping between unit cells
for i in range(N):
h00[i*4+0, i*4+0] = M
h00[i*4+1, i*4+1] = -M
h00[i*4+2, i*4+2] = M
h00[i*4+3, i*4+3] = -M
h00[i*4+0, i*4+1] = t1
h00[i*4+1, i*4+0] = t1
h00[i*4+1, i*4+2] = t1
h00[i*4+2, i*4+1] = t1
h00[i*4+2, i*4+3] = t1
h00[i*4+3, i*4+2] = t1
h00[i*4+0, i*4+2] = t2*cmath.exp(-1j*phi)
h00[i*4+2, i*4+0] = h00[i*4+0, i*4+2].conj()
h00[i*4+1, i*4+3] = t2*cmath.exp(-1j*phi)
h00[i*4+3, i*4+1] = h00[i*4+1, i*4+3].conj()
for i in range(N-1):
h00[i*4+3, (i+1)*4+0] = t1
h00[(i+1)*4+0, i*4+3] = t1
h00[i*4+2, (i+1)*4+0] = t2*cmath.exp(1j*phi)
h00[(i+1)*4+0, i*4+2] = h00[i*4+2, (i+1)*4+0].conj()
h00[i*4+3, (i+1)*4+1] = t2*cmath.exp(1j*phi)
h00[(i+1)*4+1, i*4+3] = h00[i*4+3, (i+1)*4+1].conj()
for i in range(N):
h01[i*4+1, i*4+0] = t1
h01[i*4+2, i*4+3] = t1
h01[i*4+0, i*4+0] = t2*cmath.exp(1j*phi)
h01[i*4+1, i*4+1] = t2*cmath.exp(-1j*phi)
h01[i*4+2, i*4+2] = t2*cmath.exp(1j*phi)
h01[i*4+3, i*4+3] = t2*cmath.exp(-1j*phi)
h01[i*4+1, i*4+3] = t2*cmath.exp(1j*phi)
h01[i*4+2, i*4+0] = t2*cmath.exp(-1j*phi)
if i != 0:
h01[i*4+1, (i-1)*4+3] = t2*cmath.exp(1j*phi)
for i in range(N-1):
h01[i*4+2, (i+1)*4+0] = t2*cmath.exp(-1j*phi)
hamiltonian = h00 + h01*cmath.exp(1j*k) + h01.transpose().conj()*cmath.exp(-1j*k)
return hamiltonian
def hamiltonian_of_one_QAH_model(k1, k2, t1=1, t2=1, t3=0.5, m=-1):
hamiltonian = np.zeros((2, 2), dtype=complex)
hamiltonian[0, 1] = 2*t1*cos(k1)-1j*2*t1*cos(k2)
hamiltonian[1, 0] = 2*t1*cos(k1)+1j*2*t1*cos(k2)
hamiltonian[0, 0] = m+2*t3*sin(k1)+2*t3*sin(k2)+2*t2*cos(k1+k2)
hamiltonian[1, 1] = -(m+2*t3*sin(k1)+2*t3*sin(k2)+2*t2*cos(k1+k2))
return hamiltonian
# Module 5: band structures and wave functions
## band structures
def calculate_eigenvalue(hamiltonian):
if np.array(hamiltonian).shape==():
eigenvalue = np.real(hamiltonian)
else:
eigenvalue, eigenvector = np.linalg.eigh(hamiltonian)
return eigenvalue
def calculate_eigenvalue_with_one_parameter(x_array, hamiltonian_function, print_show=0):
dim_x = np.array(x_array).shape[0]
i0 = 0
if np.array(hamiltonian_function(0)).shape==():
eigenvalue_array = np.zeros((dim_x, 1))
for x0 in x_array:
hamiltonian = hamiltonian_function(x0)
eigenvalue_array[i0, 0] = np.real(hamiltonian)
i0 += 1
else:
dim = np.array(hamiltonian_function(0)).shape[0]
eigenvalue_array = np.zeros((dim_x, dim))
for x0 in x_array:
if print_show==1:
print(x0)
hamiltonian = hamiltonian_function(x0)
eigenvalue, eigenvector = np.linalg.eigh(hamiltonian)
eigenvalue_array[i0, :] = eigenvalue
i0 += 1
return eigenvalue_array
def calculate_eigenvalue_with_two_parameters(x_array, y_array, hamiltonian_function, print_show=0, print_show_more=0):
dim_x = np.array(x_array).shape[0]
dim_y = np.array(y_array).shape[0]
if np.array(hamiltonian_function(0,0)).shape==():
eigenvalue_array = np.zeros((dim_y, dim_x, 1))
i0 = 0
for y0 in y_array:
j0 = 0
for x0 in x_array:
hamiltonian = hamiltonian_function(x0, y0)
eigenvalue_array[i0, j0, 0] = np.real(hamiltonian)
j0 += 1
i0 += 1
else:
dim = np.array(hamiltonian_function(0, 0)).shape[0]
eigenvalue_array = np.zeros((dim_y, dim_x, dim))
i0 = 0
for y0 in y_array:
j0 = 0
if print_show==1:
print(y0)
for x0 in x_array:
if print_show_more==1:
print(x0)
hamiltonian = hamiltonian_function(x0, y0)
eigenvalue, eigenvector = np.linalg.eigh(hamiltonian)
eigenvalue_array[i0, j0, :] = eigenvalue
j0 += 1
i0 += 1
return eigenvalue_array
## wave functions
def calculate_eigenvector(hamiltonian):
eigenvalue, eigenvector = np.linalg.eigh(hamiltonian)
return eigenvector
## find vector with the same gauge
def find_vector_with_the_same_gauge_with_binary_search(vector_target, vector_ref, show_error=1, show_times=0, show_phase=0, n_test=1000, precision=1e-6):
phase_1_pre = 0
phase_2_pre = np.pi
for i0 in range(n_test):
test_1 = np.sum(np.abs(vector_target*cmath.exp(1j*phase_1_pre) - vector_ref))
test_2 = np.sum(np.abs(vector_target*cmath.exp(1j*phase_2_pre) - vector_ref))
if test_1 < precision:
phase = phase_1_pre
if show_times==1:
print('Binary search times=', i0)
break
if i0 == n_test-1:
phase = phase_1_pre
if show_error==1:
print('Gauge not found with binary search times=', i0)
if test_1 < test_2:
if i0 == 0:
phase_1 = phase_1_pre-(phase_2_pre-phase_1_pre)/2
phase_2 = phase_1_pre+(phase_2_pre-phase_1_pre)/2
else:
phase_1 = phase_1_pre
phase_2 = phase_1_pre+(phase_2_pre-phase_1_pre)/2
else:
if i0 == 0:
phase_1 = phase_2_pre-(phase_2_pre-phase_1_pre)/2
phase_2 = phase_2_pre+(phase_2_pre-phase_1_pre)/2
else:
phase_1 = phase_2_pre-(phase_2_pre-phase_1_pre)/2
phase_2 = phase_2_pre
phase_1_pre = phase_1
phase_2_pre = phase_2
vector_target = vector_target*cmath.exp(1j*phase)
if show_phase==1:
print('Phase=', phase)
return vector_target
def find_vector_with_fixed_gauge_by_making_one_component_real(vector, precision=0.005, index=None):
if index == None:
index = np.argmax(np.abs(vector))
sign_pre = np.sign(np.imag(vector[index]))
for phase in np.arange(0, 2*np.pi, precision):
sign = np.sign(np.imag(vector[index]*cmath.exp(1j*phase)))
if np.abs(np.imag(vector[index]*cmath.exp(1j*phase))) < 1e-9 or sign == -sign_pre:
break
sign_pre = sign
vector = vector*cmath.exp(1j*phase)
if np.real(vector[index]) < 0:
vector = -vector
return vector
def find_vector_array_with_fixed_gauge_by_making_one_component_real(vector_array, precision=0.005):
import guan
vector_sum = 0
Num_k = np.array(vector_array).shape[0]
for i0 in range(Num_k):
vector_sum += np.abs(vector_array[i0])
index = np.argmax(np.abs(vector_sum))
for i0 in range(Num_k):
vector_array[i0] = guan.find_vector_with_fixed_gauge_by_making_one_component_real(vector_array[i0], precision=precision, index=index)
return vector_array
def rotation_of_degenerate_vectors(vector1, vector2, index1, index2, precision=0.01, criterion=0.01, show_theta=0):
import cmath
if np.abs(vector1[index2])>criterion or np.abs(vector2[index1])>criterion:
for theta in np.arange(0, 2*pi, precision):
if show_theta==1:
print(theta)
for phi1 in np.arange(0, 2*pi, precision):
for phi2 in np.arange(0, 2*pi, precision):
vector1_test = cmath.exp(1j*phi1)*vector1*cos(theta)+cmath.exp(1j*phi2)*vector2*sin(theta)
vector2_test = -cmath.exp(-1j*phi2)*vector1*sin(theta)+cmath.exp(-1j*phi1)*vector2*cos(theta)
if np.abs(vector1_test[index2])<criterion and np.abs(vector2_test[index1])<criterion:
vector1 = vector1_test
vector2 = vector2_test
break
if np.abs(vector1_test[index2])<criterion and np.abs(vector2_test[index1])<criterion:
break
if np.abs(vector1_test[index2])<criterion and np.abs(vector2_test[index1])<criterion:
break
return vector1, vector2
def rotation_of_degenerate_vectors_array(vector1_array, vector2_array, index1, index2, precision=0.01, criterion=0.01, show_theta=0):
import guan
Num_k = np.array(vector1_array).shape[0]
vector1_sum = 0
for i0 in range(Num_k):
vector1_sum += np.abs(vector1_array[i0])
index1 = np.argmax(np.abs(vector1_sum))
vector2_sum = 0
for i0 in range(Num_k):
vector1_sum += np.abs(vector2_array[i0])
index2 = np.argmax(np.abs(vector2_sum))
for i0 in range(Num_k):
vector1_array[i0], vector2_array[i0] = guan.rotation_of_degenerate_vectors(vector1=vector1_array[i0], vector2=vector2_array[i0], index1=index1, index2=index2, precision=precision, criterion=criterion, show_theta=show_theta)
return vector1_array, vector2_array
# Module 6: Green functions
def green_function(fermi_energy, hamiltonian, broadening, self_energy=0):
if np.array(hamiltonian).shape==():
dim = 1
else:
dim = np.array(hamiltonian).shape[0]
green = np.linalg.inv((fermi_energy+broadening*1j)*np.eye(dim)-hamiltonian-self_energy)
return green
def green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening, self_energy=0):
h01 = np.array(h01)
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
green_nn_n = np.linalg.inv((fermi_energy+broadening*1j)*np.identity(dim)-h00-np.dot(np.dot(h01.transpose().conj(), green_nn_n_minus), h01)-self_energy)
return green_nn_n
def green_function_in_n(green_in_n_minus, h01, green_nn_n):
green_in_n = np.dot(np.dot(green_in_n_minus, h01), green_nn_n)
return green_in_n
def green_function_ni_n(green_nn_n, h01, green_ni_n_minus):
h01 = np.array(h01)
green_ni_n = np.dot(np.dot(green_nn_n, h01.transpose().conj()), green_ni_n_minus)
return green_ni_n
def green_function_ii_n(green_ii_n_minus, green_in_n_minus, h01, green_nn_n, green_ni_n_minus):
green_ii_n = green_ii_n_minus+np.dot(np.dot(np.dot(np.dot(green_in_n_minus, h01), green_nn_n), h01.transpose().conj()),green_ni_n_minus)
return green_ii_n
def transfer_matrix(fermi_energy, h00, h01):
h01 = np.array(h01)
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
transfer = np.zeros((2*dim, 2*dim), dtype=complex)
transfer[0:dim, 0:dim] = np.dot(np.linalg.inv(h01), fermi_energy*np.identity(dim)-h00)
transfer[0:dim, dim:2*dim] = np.dot(-1*np.linalg.inv(h01), h01.transpose().conj())
transfer[dim:2*dim, 0:dim] = np.identity(dim)
transfer[dim:2*dim, dim:2*dim] = 0
return transfer
def surface_green_function_of_lead(fermi_energy, h00, h01):
h01 = np.array(h01)
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
fermi_energy = fermi_energy+1e-9*1j
transfer = transfer_matrix(fermi_energy, h00, h01)
eigenvalue, eigenvector = np.linalg.eig(transfer)
ind = np.argsort(np.abs(eigenvalue))
temp = np.zeros((2*dim, 2*dim), dtype=complex)
i0 = 0
for ind0 in ind:
temp[:, i0] = eigenvector[:, ind0]
i0 += 1
s1 = temp[dim:2*dim, 0:dim]
s2 = temp[0:dim, 0:dim]
s3 = temp[dim:2*dim, dim:2*dim]
s4 = temp[0:dim, dim:2*dim]
right_lead_surface = np.linalg.inv(fermi_energy*np.identity(dim)-h00-np.dot(np.dot(h01, s2), np.linalg.inv(s1)))
left_lead_surface = np.linalg.inv(fermi_energy*np.identity(dim)-h00-np.dot(np.dot(h01.transpose().conj(), s3), np.linalg.inv(s4)))
return right_lead_surface, left_lead_surface
def self_energy_of_lead(fermi_energy, h00, h01):
h01 = np.array(h01)
right_lead_surface, left_lead_surface = guan.surface_green_function_of_lead(fermi_energy, h00, h01)
right_self_energy = np.dot(np.dot(h01, right_lead_surface), h01.transpose().conj())
left_self_energy = np.dot(np.dot(h01.transpose().conj(), left_lead_surface), h01)
gamma_right = (right_self_energy - right_self_energy.transpose().conj())*1j
gamma_left = (left_self_energy - left_self_energy.transpose().conj())*1j
return right_self_energy, left_self_energy, gamma_right, gamma_left
def self_energy_of_lead_with_h_LC_and_h_CR(fermi_energy, h00, h01, h_LC, h_CR):
h_LC = np.array(h_LC)
h_CR = np.array(h_CR)
right_lead_surface, left_lead_surface = guan.surface_green_function_of_lead(fermi_energy, h00, h01)
right_self_energy = np.dot(np.dot(h_CR, right_lead_surface), h_CR.transpose().conj())
left_self_energy = np.dot(np.dot(h_LC.transpose().conj(), left_lead_surface), h_LC)
gamma_right = (right_self_energy - right_self_energy.transpose().conj())*1j
gamma_left = (left_self_energy - left_self_energy.transpose().conj())*1j
return right_self_energy, left_self_energy, gamma_right, gamma_left
def self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00, h01, h_lead_to_center):
h_lead_to_center = np.array(h_lead_to_center)
right_lead_surface, left_lead_surface = guan.surface_green_function_of_lead(fermi_energy, h00, h01)
self_energy = np.dot(np.dot(h_lead_to_center.transpose().conj(), right_lead_surface), h_lead_to_center)
gamma = (self_energy - self_energy.transpose().conj())*1j
return self_energy, gamma
def green_function_with_leads(fermi_energy, h00, h01, h_LC, h_CR, center_hamiltonian):
dim = np.array(center_hamiltonian).shape[0]
right_self_energy, left_self_energy, gamma_right, gamma_left = guan.self_energy_of_lead_with_h_LC_and_h_CR(fermi_energy, h00, h01, h_LC, h_CR)
green = np.linalg.inv(fermi_energy*np.identity(dim)-center_hamiltonian-left_self_energy-right_self_energy)
return green, gamma_right, gamma_left
def electron_correlation_function_green_n_for_local_current(fermi_energy, h00, h01, h_LC, h_CR, center_hamiltonian):
right_self_energy, left_self_energy, gamma_right, gamma_left = guan.self_energy_of_lead_with_h_LC_and_h_CR(fermi_energy, h00, h01, h_LC, h_CR)
green = guan.green_function(fermi_energy, center_hamiltonian, broadening=0, self_energy=left_self_energy+right_self_energy)
G_n = np.imag(np.dot(np.dot(green, gamma_left), green.transpose().conj()))
return G_n
# Module 7: density of states
def total_density_of_states(fermi_energy, hamiltonian, broadening=0.01):
green = guan.green_function(fermi_energy, hamiltonian, broadening)
total_dos = -np.trace(np.imag(green))/pi
return total_dos
def total_density_of_states_with_fermi_energy_array(fermi_energy_array, hamiltonian, broadening=0.01, print_show=0):
dim = np.array(fermi_energy_array).shape[0]
total_dos_array = np.zeros(dim)
i0 = 0
for fermi_energy in fermi_energy_array:
if print_show == 1:
print(fermi_energy)
total_dos_array[i0] = total_density_of_states(fermi_energy, hamiltonian, broadening)
i0 += 1
return total_dos_array
def local_density_of_states_for_square_lattice(fermi_energy, hamiltonian, N1, N2, internal_degree=1, broadening=0.01):
# dim_hamiltonian = N1*N2*internal_degree
green = guan.green_function(fermi_energy, hamiltonian, broadening)
local_dos = np.zeros((N2, N1))
for i1 in range(N1):
for i2 in range(N2):
for i in range(internal_degree):
local_dos[i2, i1] = local_dos[i2, i1]-np.imag(green[i1*N2*internal_degree+i2*internal_degree+i, i1*N2*internal_degree+i2*internal_degree+i])/pi
return local_dos
def local_density_of_states_for_cubic_lattice(fermi_energy, hamiltonian, N1, N2, N3, internal_degree=1, broadening=0.01):
# dim_hamiltonian = N1*N2*N3*internal_degree
green = guan.green_function(fermi_energy, hamiltonian, broadening)
local_dos = np.zeros((N3, N2, N1))
for i1 in range(N1):
for i2 in range(N2):
for i3 in range(N3):
for i in range(internal_degree):
local_dos[i3, i2, i1] = local_dos[i3, i2, i1]-np.imag(green[i1*N2*N3*internal_degree+i2*N3*internal_degree+i3*internal_degree+i, i1*N2*N3*internal_degree+i2*N3*internal_degree+i3*internal_degree+i])/pi
return local_dos
def local_density_of_states_for_square_lattice_using_dyson_equation(fermi_energy, h00, h01, N2, N1, internal_degree=1, broadening=0.01):
# dim_h00 = N2*internal_degree
local_dos = np.zeros((N2, N1))
green_11_1 = guan.green_function(fermi_energy, h00, broadening)
for i1 in range(N1):
green_nn_n_minus = green_11_1
green_in_n_minus = green_11_1
green_ni_n_minus = green_11_1
green_ii_n_minus = green_11_1
for i2_0 in range(i1):
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
if i1!=0:
green_in_n_minus = green_nn_n
green_ni_n_minus = green_nn_n
green_ii_n_minus = green_nn_n
for size_0 in range(N1-1-i1):
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
green_ii_n = guan.green_function_ii_n(green_ii_n_minus, green_in_n_minus, h01, green_nn_n, green_ni_n_minus)
green_ii_n_minus = green_ii_n
green_in_n = guan.green_function_in_n(green_in_n_minus, h01, green_nn_n)
green_in_n_minus = green_in_n
green_ni_n = guan.green_function_ni_n(green_nn_n, h01, green_ni_n_minus)
green_ni_n_minus = green_ni_n
for i2 in range(N2):
for i in range(internal_degree):
local_dos[i2, i1] = local_dos[i2, i1] - np.imag(green_ii_n_minus[i2*internal_degree+i, i2*internal_degree+i])/pi
return local_dos
def local_density_of_states_for_cubic_lattice_using_dyson_equation(fermi_energy, h00, h01, N3, N2, N1, internal_degree=1, broadening=0.01):
# dim_h00 = N2*N3*internal_degree
local_dos = np.zeros((N3, N2, N1))
green_11_1 = guan.green_function(fermi_energy, h00, broadening)
for i1 in range(N1):
green_nn_n_minus = green_11_1
green_in_n_minus = green_11_1
green_ni_n_minus = green_11_1
green_ii_n_minus = green_11_1
for i1_0 in range(i1):
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
if i1!=0:
green_in_n_minus = green_nn_n
green_ni_n_minus = green_nn_n
green_ii_n_minus = green_nn_n
for size_0 in range(N1-1-i1):
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
green_ii_n = guan.green_function_ii_n(green_ii_n_minus, green_in_n_minus, h01, green_nn_n, green_ni_n_minus)
green_ii_n_minus = green_ii_n
green_in_n = guan.green_function_in_n(green_in_n_minus, h01, green_nn_n)
green_in_n_minus = green_in_n
green_ni_n = guan.green_function_ni_n(green_nn_n, h01, green_ni_n_minus)
green_ni_n_minus = green_ni_n
for i2 in range(N2):
for i3 in range(N3):
for i in range(internal_degree):
local_dos[i3, i2, i1] = local_dos[i3, i2, i1] -np.imag(green_ii_n_minus[i2*N3*internal_degree+i3*internal_degree+i, i2*N3*internal_degree+i3*internal_degree+i])/pi
return local_dos
def local_density_of_states_for_square_lattice_with_self_energy_using_dyson_equation(fermi_energy, h00, h01, N2, N1, right_self_energy, left_self_energy, internal_degree=1, broadening=0.01):
# dim_h00 = N2*internal_degree
local_dos = np.zeros((N2, N1))
green_11_1 = guan.green_function(fermi_energy, h00+left_self_energy, broadening)
for i1 in range(N1):
green_nn_n_minus = green_11_1
green_in_n_minus = green_11_1
green_ni_n_minus = green_11_1
green_ii_n_minus = green_11_1
for i2_0 in range(i1):
if i2_0 == N1-1-1:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00+right_self_energy, h01, green_nn_n_minus, broadening)
else:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
if i1!=0:
green_in_n_minus = green_nn_n
green_ni_n_minus = green_nn_n
green_ii_n_minus = green_nn_n
for size_0 in range(N1-1-i1):
if size_0 == N1-1-i1-1:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00+right_self_energy, h01, green_nn_n_minus, broadening)
else:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n_minus, broadening)
green_nn_n_minus = green_nn_n
green_ii_n = guan.green_function_ii_n(green_ii_n_minus, green_in_n_minus, h01, green_nn_n, green_ni_n_minus)
green_ii_n_minus = green_ii_n
green_in_n = guan.green_function_in_n(green_in_n_minus, h01, green_nn_n)
green_in_n_minus = green_in_n
green_ni_n = guan.green_function_ni_n(green_nn_n, h01, green_ni_n_minus)
green_ni_n_minus = green_ni_n
for i2 in range(N2):
for i in range(internal_degree):
local_dos[i2, i1] = local_dos[i2, i1] - np.imag(green_ii_n_minus[i2*internal_degree+i, i2*internal_degree+i])/pi
return local_dos
# Module 8: quantum transport
## conductance
def calculate_conductance(fermi_energy, h00, h01, length=100):
right_self_energy, left_self_energy, gamma_right, gamma_left = guan.self_energy_of_lead(fermi_energy, h00, h01)
for ix in range(length):
if ix == 0:
green_nn_n = guan.green_function(fermi_energy, h00, broadening=0, self_energy=left_self_energy)
green_0n_n = copy.deepcopy(green_nn_n)
elif ix != length-1:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n, broadening=0)
green_0n_n = guan.green_function_in_n(green_0n_n, h01, green_nn_n)
else:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n, broadening=0, self_energy=right_self_energy)
green_0n_n = guan.green_function_in_n(green_0n_n, h01, green_nn_n)
conductance = np.trace(np.dot(np.dot(np.dot(gamma_left, green_0n_n), gamma_right), green_0n_n.transpose().conj()))
return conductance
def calculate_conductance_with_fermi_energy_array(fermi_energy_array, h00, h01, length=100, print_show=0):
dim = np.array(fermi_energy_array).shape[0]
conductance_array = np.zeros(dim)
i0 = 0
for fermi_energy in fermi_energy_array:
if print_show == 1:
print(fermi_energy)
conductance_array[i0] = np.real(calculate_conductance(fermi_energy, h00, h01, length))
i0 += 1
return conductance_array
def calculate_conductance_with_disorder(fermi_energy, h00, h01, disorder_intensity=2.0, disorder_concentration=1.0, length=100):
right_self_energy, left_self_energy, gamma_right, gamma_left = guan.self_energy_of_lead(fermi_energy, h00, h01)
dim = np.array(h00).shape[0]
for ix in range(length):
disorder = np.zeros((dim, dim))
for dim0 in range(dim):
if np.random.uniform(0, 1)<=disorder_concentration:
disorder[dim0, dim0] = np.random.uniform(-disorder_intensity, disorder_intensity)
if ix == 0:
green_nn_n = guan.green_function(fermi_energy, h00+disorder, broadening=0, self_energy=left_self_energy)
green_0n_n = copy.deepcopy(green_nn_n)
elif ix != length-1:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00+disorder, h01, green_nn_n, broadening=0)
green_0n_n = guan.green_function_in_n(green_0n_n, h01, green_nn_n)
else:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00+disorder, h01, green_nn_n, broadening=0, self_energy=right_self_energy)
green_0n_n = guan.green_function_in_n(green_0n_n, h01, green_nn_n)
conductance = np.trace(np.dot(np.dot(np.dot(gamma_left, green_0n_n), gamma_right), green_0n_n.transpose().conj()))
return conductance
def calculate_conductance_with_disorder_intensity_array(fermi_energy, h00, h01, disorder_intensity_array, disorder_concentration=1.0, length=100, calculation_times=1, print_show=0):
dim = np.array(disorder_intensity_array).shape[0]
conductance_array = np.zeros(dim)
i0 = 0
for disorder_intensity in disorder_intensity_array:
if print_show == 1:
print(disorder_intensity)
for times in range(calculation_times):
conductance_array[i0] = conductance_array[i0]+np.real(calculate_conductance_with_disorder(fermi_energy, h00, h01, disorder_intensity=disorder_intensity, disorder_concentration=disorder_concentration, length=length))
i0 += 1
conductance_array = conductance_array/calculation_times
return conductance_array
def calculate_conductance_with_disorder_concentration_array(fermi_energy, h00, h01, disorder_concentration_array, disorder_intensity=2.0, length=100, calculation_times=1, print_show=0):
dim = np.array(disorder_concentration_array).shape[0]
conductance_array = np.zeros(dim)
i0 = 0
for disorder_concentration in disorder_concentration_array:
if print_show == 1:
print(disorder_concentration)
for times in range(calculation_times):
conductance_array[i0] = conductance_array[i0]+np.real(calculate_conductance_with_disorder(fermi_energy, h00, h01, disorder_intensity=disorder_intensity, disorder_concentration=disorder_concentration, length=length))
i0 += 1
conductance_array = conductance_array/calculation_times
return conductance_array
def calculate_conductance_with_scattering_length_array(fermi_energy, h00, h01, length_array, disorder_intensity=2.0, disorder_concentration=1.0, calculation_times=1, print_show=0):
dim = np.array(length_array).shape[0]
conductance_array = np.zeros(dim)
i0 = 0
for length in length_array:
if print_show == 1:
print(length)
for times in range(calculation_times):
conductance_array[i0] = conductance_array[i0]+np.real(calculate_conductance_with_disorder(fermi_energy, h00, h01, disorder_intensity=disorder_intensity, disorder_concentration=disorder_concentration, length=length))
i0 += 1
conductance_array = conductance_array/calculation_times
return conductance_array
## multi-terminal transmission
def get_gamma_array_and_green_for_six_terminal_transmission(fermi_energy, h00_for_lead_4, h01_for_lead_4, h00_for_lead_2, h01_for_lead_2, center_hamiltonian, width=10, length=50, internal_degree=1, moving_step_of_leads=10):
# ---------------- Geometry ----------------
# lead2 lead3
# lead1(L) lead4(R)
# lead6 lead5
# h00 and h01 in leads
h00_for_lead_1 = h00_for_lead_4
h00_for_lead_2 = h00_for_lead_2
h00_for_lead_3 = h00_for_lead_2
h00_for_lead_5 = h00_for_lead_2
h00_for_lead_6 = h00_for_lead_2
h00_for_lead_4 = h00_for_lead_4
h01_for_lead_1 = h01_for_lead_4.transpose().conj()
h01_for_lead_2 = h01_for_lead_2
h01_for_lead_3 = h01_for_lead_2
h01_for_lead_4 = h01_for_lead_4
h01_for_lead_5 = h01_for_lead_2.transpose().conj()
h01_for_lead_6 = h01_for_lead_2.transpose().conj()
# hopping matrix from lead to center
h_lead1_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
h_lead2_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
h_lead3_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
h_lead4_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
h_lead5_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
h_lead6_to_center = np.zeros((internal_degree*width, internal_degree*width*length), dtype=complex)
move = moving_step_of_leads # the step of leads 2,3,6,5 moving to center
h_lead1_to_center[0:internal_degree*width, 0:internal_degree*width] = h01_for_lead_1.transpose().conj()
h_lead4_to_center[0:internal_degree*width, internal_degree*width*(length-1):internal_degree*width*length] = h01_for_lead_4.transpose().conj()
for i0 in range(width):
begin_index = internal_degree*i0+0
end_index = internal_degree*i0+internal_degree
h_lead2_to_center[begin_index:end_index, internal_degree*(width*(move+i0)+(width-1))+0:internal_degree*(width*(move+i0)+(width-1))+internal_degree] = h01_for_lead_2.transpose().conj()[begin_index:end_index, begin_index:end_index]
h_lead3_to_center[begin_index:end_index, internal_degree*(width*(length-move-1-i0)+(width-1))+0:internal_degree*(width*(length-move-1-i0)+(width-1))+internal_degree] = h01_for_lead_3.transpose().conj()[begin_index:end_index, begin_index:end_index]
h_lead5_to_center[begin_index:end_index, internal_degree*(width*(length-move-1-i0)+0)+0:internal_degree*(width*(length-move-1-i0)+0)+internal_degree] = h01_for_lead_5.transpose().conj()[begin_index:end_index, begin_index:end_index]
h_lead6_to_center[begin_index:end_index, internal_degree*(width*(i0+move)+0)+0:internal_degree*(width*(i0+move)+0)+internal_degree] = h01_for_lead_6.transpose().conj()[begin_index:end_index, begin_index:end_index]
# self energy
self_energy1, gamma1 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_1, h01_for_lead_1, h_lead1_to_center)
self_energy2, gamma2 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_2, h01_for_lead_1, h_lead2_to_center)
self_energy3, gamma3 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_3, h01_for_lead_1, h_lead3_to_center)
self_energy4, gamma4 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_4, h01_for_lead_1, h_lead4_to_center)
self_energy5, gamma5 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_5, h01_for_lead_1, h_lead5_to_center)
self_energy6, gamma6 = guan.self_energy_of_lead_with_h_lead_to_center(fermi_energy, h00_for_lead_6, h01_for_lead_1, h_lead6_to_center)
gamma_array = [gamma1, gamma2, gamma3, gamma4, gamma5, gamma6]
# Green function
green = np.linalg.inv(fermi_energy*np.eye(internal_degree*width*length)-center_hamiltonian-self_energy1-self_energy2-self_energy3-self_energy4-self_energy5-self_energy6)
return gamma_array, green
def calculate_six_terminal_transmission_matrix(fermi_energy, h00_for_lead_4, h01_for_lead_4, h00_for_lead_2, h01_for_lead_2, center_hamiltonian, width=10, length=50, internal_degree=1, moving_step_of_leads=10):
gamma_array, green = guan.get_gamma_array_and_green_for_six_terminal_transmission(fermi_energy, h00_for_lead_4, h01_for_lead_4, h00_for_lead_2, h01_for_lead_2, center_hamiltonian, width, length, internal_degree, moving_step_of_leads)
# Transmission
transmission_matrix = np.zeros((6, 6), dtype=complex)
channel_lead_4 = guan.calculate_conductance(fermi_energy, h00_for_lead_4, h01_for_lead_4, length=3)
channel_lead_2 = guan.calculate_conductance(fermi_energy, h00_for_lead_2, h01_for_lead_2, length=3)
for i0 in range(6):
for j0 in range(6):
if j0!=i0:
transmission_matrix[i0, j0] = np.trace(np.dot(np.dot(np.dot(gamma_array[i0], green), gamma_array[j0]), green.transpose().conj()))
for i0 in range(6):
if i0 == 0 or i0 == 3:
transmission_matrix[i0, i0] = channel_lead_4
else:
transmission_matrix[i0, i0] = channel_lead_2
for i0 in range(6):
for j0 in range(6):
if j0!=i0:
transmission_matrix[i0, i0] = transmission_matrix[i0, i0]-transmission_matrix[i0, j0]
transmission_matrix = np.real(transmission_matrix)
return transmission_matrix
def calculate_six_terminal_transmissions_from_lead_1(fermi_energy, h00_for_lead_4, h01_for_lead_4, h00_for_lead_2, h01_for_lead_2, center_hamiltonian, width=10, length=50, internal_degree=1, moving_step_of_leads=10):
gamma_array, green = guan.get_gamma_array_and_green_for_six_terminal_transmission(fermi_energy, h00_for_lead_4, h01_for_lead_4, h00_for_lead_2, h01_for_lead_2, center_hamiltonian, width, length, internal_degree, moving_step_of_leads)
# Transmission
transmission_12 = np.real(np.trace(np.dot(np.dot(np.dot(gamma_array[0], green), gamma_array[1]), green.transpose().conj())))
transmission_13 = np.real(np.trace(np.dot(np.dot(np.dot(gamma_array[0], green), gamma_array[2]), green.transpose().conj())))
transmission_14 = np.real(np.trace(np.dot(np.dot(np.dot(gamma_array[0], green), gamma_array[3]), green.transpose().conj())))
transmission_15 = np.real(np.trace(np.dot(np.dot(np.dot(gamma_array[0], green), gamma_array[4]), green.transpose().conj())))
transmission_16 = np.real(np.trace(np.dot(np.dot(np.dot(gamma_array[0], green), gamma_array[5]), green.transpose().conj())))
return transmission_12, transmission_13, transmission_14, transmission_15, transmission_16
## scattering matrix
def if_active_channel(k_of_channel):
if np.abs(np.imag(k_of_channel))<1e-6:
if_active = 1
else:
if_active = 0
return if_active
def get_k_and_velocity_of_channel(fermi_energy, h00, h01):
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
transfer = guan.transfer_matrix(fermi_energy, h00, h01)
eigenvalue, eigenvector = np.linalg.eig(transfer)
k_of_channel = np.log(eigenvalue)/1j
ind = np.argsort(np.real(k_of_channel))
k_of_channel = np.sort(k_of_channel)
temp = np.zeros((2*dim, 2*dim), dtype=complex)
temp2 = np.zeros((2*dim), dtype=complex)
i0 = 0
for ind0 in ind:
temp[:, i0] = eigenvector[:, ind0]
temp2[i0] = eigenvalue[ind0]
i0 += 1
eigenvalue = copy.deepcopy(temp2)
temp = temp[0:dim, :]
factor = np.zeros(2*dim, dtype=complex)
for dim0 in range(dim):
factor = factor+np.square(np.abs(temp[dim0, :]))
for dim0 in range(2*dim):
temp[:, dim0] = temp[:, dim0]/np.sqrt(factor[dim0])
velocity_of_channel = np.zeros((2*dim), dtype=complex)
for dim0 in range(2*dim):
velocity_of_channel[dim0] = eigenvalue[dim0]*np.dot(np.dot(temp[0:dim, :].transpose().conj(), h01),temp[0:dim, :])[dim0, dim0]
velocity_of_channel = -2*np.imag(velocity_of_channel)
eigenvector = copy.deepcopy(temp)
return k_of_channel, velocity_of_channel, eigenvalue, eigenvector
def get_classified_k_velocity_u_and_f(fermi_energy, h00, h01):
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
k_of_channel, velocity_of_channel, eigenvalue, eigenvector = get_k_and_velocity_of_channel(fermi_energy, h00, h01)
ind_right_active = 0; ind_right_evanescent = 0; ind_left_active = 0; ind_left_evanescent = 0
k_right = np.zeros(dim, dtype=complex); k_left = np.zeros(dim, dtype=complex)
velocity_right = np.zeros(dim, dtype=complex); velocity_left = np.zeros(dim, dtype=complex)
lambda_right = np.zeros(dim, dtype=complex); lambda_left = np.zeros(dim, dtype=complex)
u_right = np.zeros((dim, dim), dtype=complex); u_left = np.zeros((dim, dim), dtype=complex)
for dim0 in range(2*dim):
if_active = if_active_channel(k_of_channel[dim0])
if if_active_channel(k_of_channel[dim0]) == 1:
direction = np.sign(velocity_of_channel[dim0])
else:
direction = np.sign(np.imag(k_of_channel[dim0]))
if direction == 1:
if if_active == 1: # right-moving active channel
k_right[ind_right_active] = k_of_channel[dim0]
velocity_right[ind_right_active] = velocity_of_channel[dim0]
lambda_right[ind_right_active] = eigenvalue[dim0]
u_right[:, ind_right_active] = eigenvector[:, dim0]
ind_right_active += 1
else: # right-moving evanescent channel
k_right[dim-1-ind_right_evanescent] = k_of_channel[dim0]
velocity_right[dim-1-ind_right_evanescent] = velocity_of_channel[dim0]
lambda_right[dim-1-ind_right_evanescent] = eigenvalue[dim0]
u_right[:, dim-1-ind_right_evanescent] = eigenvector[:, dim0]
ind_right_evanescent += 1
else:
if if_active == 1: # left-moving active channel
k_left[ind_left_active] = k_of_channel[dim0]
velocity_left[ind_left_active] = velocity_of_channel[dim0]
lambda_left[ind_left_active] = eigenvalue[dim0]
u_left[:, ind_left_active] = eigenvector[:, dim0]
ind_left_active += 1
else: # left-moving evanescent channel
k_left[dim-1-ind_left_evanescent] = k_of_channel[dim0]
velocity_left[dim-1-ind_left_evanescent] = velocity_of_channel[dim0]
lambda_left[dim-1-ind_left_evanescent] = eigenvalue[dim0]
u_left[:, dim-1-ind_left_evanescent] = eigenvector[:, dim0]
ind_left_evanescent += 1
lambda_matrix_right = np.diag(lambda_right)
lambda_matrix_left = np.diag(lambda_left)
f_right = np.dot(np.dot(u_right, lambda_matrix_right), np.linalg.inv(u_right))
f_left = np.dot(np.dot(u_left, lambda_matrix_left), np.linalg.inv(u_left))
return k_right, k_left, velocity_right, velocity_left, f_right, f_left, u_right, u_left, ind_right_active
def calculate_scattering_matrix(fermi_energy, h00, h01, length=100):
h01 = np.array(h01)
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
k_right, k_left, velocity_right, velocity_left, f_right, f_left, u_right, u_left, ind_right_active = get_classified_k_velocity_u_and_f(fermi_energy, h00, h01)
right_self_energy = np.dot(h01, f_right)
left_self_energy = np.dot(h01.transpose().conj(), np.linalg.inv(f_left))
for i0 in range(length):
if i0 == 0:
green_nn_n = guan.green_function(fermi_energy, h00, broadening=0, self_energy=left_self_energy)
green_00_n = copy.deepcopy(green_nn_n)
green_0n_n = copy.deepcopy(green_nn_n)
green_n0_n = copy.deepcopy(green_nn_n)
elif i0 != length-1:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n, broadening=0)
else:
green_nn_n = guan.green_function_nn_n(fermi_energy, h00, h01, green_nn_n, broadening=0, self_energy=right_self_energy)
green_00_n = guan.green_function_ii_n(green_00_n, green_0n_n, h01, green_nn_n, green_n0_n)
green_0n_n = guan.green_function_in_n(green_0n_n, h01, green_nn_n)
green_n0_n = guan.green_function_ni_n(green_nn_n, h01, green_n0_n)
temp = np.dot(h01.transpose().conj(), np.linalg.inv(f_right)-np.linalg.inv(f_left))
transmission_matrix = np.dot(np.dot(np.linalg.inv(u_right), np.dot(green_n0_n, temp)), u_right)
reflection_matrix = np.dot(np.dot(np.linalg.inv(u_left), np.dot(green_00_n, temp)-np.identity(dim)), u_right)
for dim0 in range(dim):
for dim1 in range(dim):
if_active = if_active_channel(k_right[dim0])*if_active_channel(k_right[dim1])
if if_active == 1:
transmission_matrix[dim0, dim1] = np.sqrt(np.abs(velocity_right[dim0]/velocity_right[dim1])) * transmission_matrix[dim0, dim1]
reflection_matrix[dim0, dim1] = np.sqrt(np.abs(velocity_left[dim0]/velocity_right[dim1]))*reflection_matrix[dim0, dim1]
else:
transmission_matrix[dim0, dim1] = 0
reflection_matrix[dim0, dim1] = 0
sum_of_tran_refl_array = np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active])), axis=0)+np.sum(np.square(np.abs(reflection_matrix[0:ind_right_active, 0:ind_right_active])), axis=0)
for sum_of_tran_refl in sum_of_tran_refl_array:
if sum_of_tran_refl > 1.001:
print('Error Alert: scattering matrix is not normalized!')
return transmission_matrix, reflection_matrix, k_right, k_left, velocity_right, velocity_left, ind_right_active
def print_or_write_scattering_matrix(fermi_energy, h00, h01, length=100, print_show=1, write_file=0, filename='a', format='txt'):
if np.array(h00).shape==():
dim = 1
else:
dim = np.array(h00).shape[0]
transmission_matrix, reflection_matrix, k_right, k_left, velocity_right, velocity_left, ind_right_active = calculate_scattering_matrix(fermi_energy, h00, h01, length)
if print_show == 1:
print('\nActive channel (left or right) = ', ind_right_active)
print('Evanescent channel (left or right) = ', dim-ind_right_active, '\n')
print('K of right-moving active channels:\n', np.real(k_right[0:ind_right_active]))
print('K of left-moving active channels:\n', np.real(k_left[0:ind_right_active]), '\n')
print('Velocity of right-moving active channels:\n', np.real(velocity_right[0:ind_right_active]))
print('Velocity of left-moving active channels:\n', np.real(velocity_left[0:ind_right_active]), '\n')
print('Transmission matrix:\n', np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active])))
print('Reflection matrix:\n', np.square(np.abs(reflection_matrix[0:ind_right_active, 0:ind_right_active])), '\n')
print('Total transmission of channels:\n', np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active])), axis=0))
print('Total reflection of channels:\n',np.sum(np.square(np.abs(reflection_matrix[0:ind_right_active, 0:ind_right_active])), axis=0))
print('Sum of transmission and reflection of channels:\n', np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active])), axis=0) + np.sum(np.square(np.abs(reflection_matrix[0:ind_right_active, 0:ind_right_active])), axis=0))
print('Total conductance = ', np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active]))), '\n')
if write_file == 1:
with open(filename+'.'+format, 'w') as f:
f.write('Active channel (left or right) = ' + str(ind_right_active) + '\n')
f.write('Evanescent channel (left or right) = ' + str(dim - ind_right_active) + '\n\n')
f.write('Channel K Velocity\n')
for ind0 in range(ind_right_active):
f.write(' '+str(ind0 + 1) + ' | '+str(np.real(k_right[ind0]))+' ' + str(np.real(velocity_right[ind0]))+'\n')
f.write('\n')
for ind0 in range(ind_right_active):
f.write(' -' + str(ind0 + 1) + ' | ' + str(np.real(k_left[ind0])) + ' ' + str(np.real(velocity_left[ind0])) + '\n')
f.write('\nScattering matrix:\n ')
for ind0 in range(ind_right_active):
f.write(str(ind0+1)+' ')
f.write('\n')
for ind1 in range(ind_right_active):
f.write(' '+str(ind1+1)+' ')
for ind2 in range(ind_right_active):
f.write('%f' % np.square(np.abs(transmission_matrix[ind1, ind2]))+' ')
f.write('\n')
f.write('\n')
for ind1 in range(ind_right_active):
f.write(' -'+str(ind1+1)+' ')
for ind2 in range(ind_right_active):
f.write('%f' % np.square(np.abs(reflection_matrix[ind1, ind2]))+' ')
f.write('\n')
f.write('\n')
f.write('Total transmission of channels:\n'+str(np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active])), axis=0))+'\n')
f.write('Total conductance = '+str(np.sum(np.square(np.abs(transmission_matrix[0:ind_right_active, 0:ind_right_active]))))+'\n')
# Module 9: topological invariant
def calculate_chern_number_for_square_lattice(hamiltonian_function, precision=100, print_show=0):
if np.array(hamiltonian_function(0, 0)).shape==():
dim = 1
else:
dim = np.array(hamiltonian_function(0, 0)).shape[0]
delta = 2*pi/precision
chern_number = np.zeros(dim, dtype=complex)
for kx in np.arange(-pi, pi, delta):
if print_show == 1:
print(kx)
for ky in np.arange(-pi, pi, delta):
H = hamiltonian_function(kx, ky)
vector = guan.calculate_eigenvector(H)
H_delta_kx = hamiltonian_function(kx+delta, ky)
vector_delta_kx = guan.calculate_eigenvector(H_delta_kx)
H_delta_ky = hamiltonian_function(kx, ky+delta)
vector_delta_ky = guan.calculate_eigenvector(H_delta_ky)
H_delta_kx_ky = hamiltonian_function(kx+delta, ky+delta)
vector_delta_kx_ky = guan.calculate_eigenvector(H_delta_kx_ky)
for i in range(dim):
vector_i = vector[:, i]
vector_delta_kx_i = vector_delta_kx[:, i]
vector_delta_ky_i = vector_delta_ky[:, i]
vector_delta_kx_ky_i = vector_delta_kx_ky[:, i]
Ux = np.dot(np.conj(vector_i), vector_delta_kx_i)/abs(np.dot(np.conj(vector_i), vector_delta_kx_i))
Uy = np.dot(np.conj(vector_i), vector_delta_ky_i)/abs(np.dot(np.conj(vector_i), vector_delta_ky_i))
Ux_y = np.dot(np.conj(vector_delta_ky_i), vector_delta_kx_ky_i)/abs(np.dot(np.conj(vector_delta_ky_i), vector_delta_kx_ky_i))
Uy_x = np.dot(np.conj(vector_delta_kx_i), vector_delta_kx_ky_i)/abs(np.dot(np.conj(vector_delta_kx_i), vector_delta_kx_ky_i))
F = cmath.log(Ux*Uy_x*(1/Ux_y)*(1/Uy))
chern_number[i] = chern_number[i] + F
chern_number = chern_number/(2*pi*1j)
return chern_number
def calculate_chern_number_for_square_lattice_with_Wilson_loop(hamiltonian_function, precision_of_plaquettes=10, precision_of_Wilson_loop=100, print_show=0):
delta = 2*pi/precision_of_plaquettes
chern_number = 0
for kx in np.arange(-pi, pi, delta):
if print_show == 1:
print(kx)
for ky in np.arange(-pi, pi, delta):
vector_array = []
# line_1
for i0 in range(precision_of_Wilson_loop+1):
H_delta = hamiltonian_function(kx+delta/precision_of_Wilson_loop*i0, ky)
eigenvalue, eigenvector = np.linalg.eig(H_delta)
vector_delta = eigenvector[:, np.argsort(np.real(eigenvalue))]
vector_array.append(vector_delta)
# line_2
for i0 in range(precision_of_Wilson_loop):
H_delta = hamiltonian_function(kx+delta, ky+delta/precision_of_Wilson_loop*(i0+1))
eigenvalue, eigenvector = np.linalg.eig(H_delta)
vector_delta = eigenvector[:, np.argsort(np.real(eigenvalue))]
vector_array.append(vector_delta)
# line_3
for i0 in range(precision_of_Wilson_loop):
H_delta = hamiltonian_function(kx+delta-delta/precision_of_Wilson_loop*(i0+1), ky+delta)
eigenvalue, eigenvector = np.linalg.eig(H_delta)
vector_delta = eigenvector[:, np.argsort(np.real(eigenvalue))]
vector_array.append(vector_delta)
# line_4
for i0 in range(precision_of_Wilson_loop-1):
H_delta = hamiltonian_function(kx, ky+delta-delta/precision_of_Wilson_loop*(i0+1))
eigenvalue, eigenvector = np.linalg.eig(H_delta)
vector_delta = eigenvector[:, np.argsort(np.real(eigenvalue))]
vector_array.append(vector_delta)
Wilson_loop = 1
for i0 in range(len(vector_array)-1):
Wilson_loop = Wilson_loop*np.dot(vector_array[i0].transpose().conj(), vector_array[i0+1])
Wilson_loop = Wilson_loop*np.dot(vector_array[len(vector_array)-1].transpose().conj(), vector_array[0])
arg = np.log(np.diagonal(Wilson_loop))/1j
chern_number = chern_number + arg
chern_number = chern_number/(2*pi)
return chern_number
def calculate_chern_number_for_honeycomb_lattice(hamiltonian_function, a=1, precision=300, print_show=0):
if np.array(hamiltonian_function(0, 0)).shape==():
dim = 1
else:
dim = np.array(hamiltonian_function(0, 0)).shape[0]
chern_number = np.zeros(dim, dtype=complex)
L1 = 4*sqrt(3)*pi/9/a
L2 = 2*sqrt(3)*pi/9/a
L3 = 2*pi/3/a
delta1 = 2*L1/precision
delta3 = 2*L3/precision
for kx in np.arange(-L1, L1, delta1):
if print_show == 1:
print(kx)
for ky in np.arange(-L3, L3, delta3):
if (-L2<=kx<=L2) or (kx>L2 and -(L1-kx)*tan(pi/3)<=ky<=(L1-kx)*tan(pi/3)) or (kx<-L2 and -(kx-(-L1))*tan(pi/3)<=ky<=(kx-(-L1))*tan(pi/3)):
H = hamiltonian_function(kx, ky)
vector = guan.calculate_eigenvector(H)
H_delta_kx = hamiltonian_function(kx+delta1, ky)
vector_delta_kx = guan.calculate_eigenvector(H_delta_kx)
H_delta_ky = hamiltonian_function(kx, ky+delta3)
vector_delta_ky = guan.calculate_eigenvector(H_delta_ky)
H_delta_kx_ky = hamiltonian_function(kx+delta1, ky+delta3)
vector_delta_kx_ky = guan.calculate_eigenvector(H_delta_kx_ky)
for i in range(dim):
vector_i = vector[:, i]
vector_delta_kx_i = vector_delta_kx[:, i]
vector_delta_ky_i = vector_delta_ky[:, i]
vector_delta_kx_ky_i = vector_delta_kx_ky[:, i]
Ux = np.dot(np.conj(vector_i), vector_delta_kx_i)/abs(np.dot(np.conj(vector_i), vector_delta_kx_i))
Uy = np.dot(np.conj(vector_i), vector_delta_ky_i)/abs(np.dot(np.conj(vector_i), vector_delta_ky_i))
Ux_y = np.dot(np.conj(vector_delta_ky_i), vector_delta_kx_ky_i)/abs(np.dot(np.conj(vector_delta_ky_i), vector_delta_kx_ky_i))
Uy_x = np.dot(np.conj(vector_delta_kx_i), vector_delta_kx_ky_i)/abs(np.dot(np.conj(vector_delta_kx_i), vector_delta_kx_ky_i))
F = cmath.log(Ux*Uy_x*(1/Ux_y)*(1/Uy))
chern_number[i] = chern_number[i] + F
chern_number = chern_number/(2*pi*1j)
return chern_number
def calculate_wilson_loop(hamiltonian_function, k_min=-pi, k_max=pi, precision=100, print_show=0):
k_array = np.linspace(k_min, k_max, precision)
dim = np.array(hamiltonian_function(0)).shape[0]
wilson_loop_array = np.ones(dim, dtype=complex)
for i in range(dim):
if print_show == 1:
print(i)
eigenvector_array = []
for k in k_array:
eigenvector = guan.calculate_eigenvector(hamiltonian_function(k))
if k != k_max:
eigenvector_array.append(eigenvector[:, i])
else:
eigenvector_array.append(eigenvector_array[0])
for i0 in range(precision-1):
F = np.dot(eigenvector_array[i0+1].transpose().conj(), eigenvector_array[i0])
wilson_loop_array[i] = np.dot(F, wilson_loop_array[i])
return wilson_loop_array
# Module 10: read and write
def read_one_dimensional_data(filename='a', format='txt'):
f = open(filename+'.'+format, 'r')
text = f.read()
f.close()
row_list = np.array(text.split('\n'))
dim_column = np.array(row_list[0].split()).shape[0]
x_array = np.array([])
y_array = np.array([])
for row in row_list:
column = np.array(row.split())
if column.shape[0] != 0:
x_array = np.append(x_array, [float(column[0])], axis=0)
y_row = np.zeros(dim_column-1)
for dim0 in range(dim_column-1):
y_row[dim0] = float(column[dim0+1])
if np.array(y_array).shape[0] == 0:
y_array = [y_row]
else:
y_array = np.append(y_array, [y_row], axis=0)
return x_array, y_array
def read_two_dimensional_data(filename='a', format='txt'):
f = open(filename+'.'+format, 'r')
text = f.read()
f.close()
row_list = np.array(text.split('\n'))
dim_column = np.array(row_list[0].split()).shape[0]
x_array = np.array([])
y_array = np.array([])
matrix = np.array([])
for i0 in range(row_list.shape[0]):
column = np.array(row_list[i0].split())
if i0 == 0:
x_str = column[1::]
x_array = np.zeros(x_str.shape[0])
for i00 in range(x_str.shape[0]):
x_array[i00] = float(x_str[i00])
elif column.shape[0] != 0:
y_array = np.append(y_array, [float(column[0])], axis=0)
matrix_row = np.zeros(dim_column-1)
for dim0 in range(dim_column-1):
matrix_row[dim0] = float(column[dim0+1])
if np.array(matrix).shape[0] == 0:
matrix = [matrix_row]
else:
matrix = np.append(matrix, [matrix_row], axis=0)
return x_array, y_array, matrix
def write_one_dimensional_data(x_array, y_array, filename='a', format='txt'):
x_array = np.array(x_array)
y_array = np.array(y_array)
with open(filename+'.'+format, 'w') as f:
i0 = 0
for x0 in x_array:
f.write(str(x0)+' ')
if len(y_array.shape) == 1:
f.write(str(y_array[i0])+'\n')
elif len(y_array.shape) == 2:
for j0 in range(y_array.shape[1]):
f.write(str(y_array[i0, j0])+' ')
f.write('\n')
i0 += 1
def write_two_dimensional_data(x_array, y_array, matrix, filename='a', format='txt'):
x_array = np.array(x_array)
y_array = np.array(y_array)
matrix = np.array(matrix)
with open(filename+'.'+format, 'w') as f:
f.write('0 ')
for x0 in x_array:
f.write(str(x0)+' ')
f.write('\n')
i0 = 0
for y0 in y_array:
f.write(str(y0))
j0 = 0
for x0 in x_array:
f.write(' '+str(matrix[i0, j0])+' ')
j0 += 1
f.write('\n')
i0 += 1
# Module 11: plot figures
def plot(x_array, y_array, xlabel='x', ylabel='y', title='', show=1, save=0, filename='a', format='jpg', dpi=300, type='', y_min=None, y_max=None, linewidth=None, markersize=None):
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
plt.subplots_adjust(bottom=0.20, left=0.18)
ax.plot(x_array, y_array, type, linewidth=linewidth, markersize=markersize)
ax.grid()
ax.set_title(title, fontsize=20, fontfamily='Times New Roman')
ax.set_xlabel(xlabel, fontsize=20, fontfamily='Times New Roman')
ax.set_ylabel(ylabel, fontsize=20, fontfamily='Times New Roman')
if y_min!=None or y_max!=None:
if y_min==None:
y_min=min(y_array)
if y_max==None:
y_max=max(y_array)
ax.set_ylim(y_min, y_max)
ax.tick_params(labelsize=20)
labels = ax.get_xticklabels() + ax.get_yticklabels()
[label.set_fontname('Times New Roman') for label in labels]
if save == 1:
plt.savefig(filename+'.'+format, dpi=dpi)
if show == 1:
plt.show()
plt.close('all')
def plot_3d_surface(x_array, y_array, matrix, xlabel='x', ylabel='y', zlabel='z', title='', show=1, save=0, filename='a', format='jpg', dpi=300, z_min=None, z_max=None, rcount=100, ccount=100):
import matplotlib.pyplot as plt
from matplotlib import cm
from matplotlib.ticker import LinearLocator
matrix = np.array(matrix)
fig, ax = plt.subplots(subplot_kw={"projection": "3d"})
plt.subplots_adjust(bottom=0.1, right=0.65)
x_array, y_array = np.meshgrid(x_array, y_array)
if len(matrix.shape) == 2:
surf = ax.plot_surface(x_array, y_array, matrix, rcount=rcount, ccount=ccount, cmap=cm.coolwarm, linewidth=0, antialiased=False)
elif len(matrix.shape) == 3:
for i0 in range(matrix.shape[2]):
surf = ax.plot_surface(x_array, y_array, matrix[:,:,i0], rcount=rcount, ccount=ccount, cmap=cm.coolwarm, linewidth=0, antialiased=False)
ax.set_title(title, fontsize=20, fontfamily='Times New Roman')
ax.set_xlabel(xlabel, fontsize=20, fontfamily='Times New Roman')
ax.set_ylabel(ylabel, fontsize=20, fontfamily='Times New Roman')
ax.set_zlabel(zlabel, fontsize=20, fontfamily='Times New Roman')
ax.zaxis.set_major_locator(LinearLocator(5))
ax.zaxis.set_major_formatter('{x:.2f}')
if z_min!=None or z_max!=None:
if z_min==None:
z_min=matrix.min()
if z_max==None:
z_max=matrix.max()
ax.set_zlim(z_min, z_max)
ax.tick_params(labelsize=15)
labels = ax.get_xticklabels() + ax.get_yticklabels() + ax.get_zticklabels()
[label.set_fontname('Times New Roman') for label in labels]
cax = plt.axes([0.80, 0.15, 0.05, 0.75])
cbar = fig.colorbar(surf, cax=cax)
cbar.ax.tick_params(labelsize=15)
for l in cbar.ax.yaxis.get_ticklabels():
l.set_family('Times New Roman')
if save == 1:
plt.savefig(filename+'.'+format, dpi=dpi)
if show == 1:
plt.show()
plt.close('all')
def plot_contour(x_array, y_array, matrix, xlabel='x', ylabel='y', title='', show=1, save=0, filename='a', format='jpg', dpi=300):
import matplotlib.pyplot as plt
fig, ax = plt.subplots()
plt.subplots_adjust(bottom=0.2, right=0.75, left = 0.16)
x_array, y_array = np.meshgrid(x_array, y_array)
contour = ax.contourf(x_array,y_array,matrix,cmap='jet')
ax.set_title(title, fontsize=20, fontfamily='Times New Roman')
ax.set_xlabel(xlabel, fontsize=20, fontfamily='Times New Roman')
ax.set_ylabel(ylabel, fontsize=20, fontfamily='Times New Roman')
ax.tick_params(labelsize=15)
labels = ax.get_xticklabels() + ax.get_yticklabels()
[label.set_fontname('Times New Roman') for label in labels]
cax = plt.axes([0.78, 0.17, 0.08, 0.71])
cbar = fig.colorbar(contour, cax=cax)
cbar.ax.tick_params(labelsize=15)
for l in cbar.ax.yaxis.get_ticklabels():
l.set_family('Times New Roman')
if save == 1:
plt.savefig(filename+'.'+format, dpi=dpi)
if show == 1:
plt.show()
plt.close('all')
# Module 12: data processing
def preprocess_for_parallel_calculations(parameter_array_all, cpus=1, task_index=0):
num_all = np.array(parameter_array_all).shape[0]
if num_all%cpus == 0:
num_parameter = int(num_all/cpus)
parameter_array = parameter_array_all[task_index*num_parameter:(task_index+1)*num_parameter]
else:
num_parameter = int(num_all/(cpus-1))
if task_index != cpus-1:
parameter_array = parameter_array_all[task_index*num_parameter:(task_index+1)*num_parameter]
else:
parameter_array = parameter_array_all[task_index*num_parameter:num_all]
return parameter_array
def change_directory_by_replacement(current_key_word='codes', new_key_word='data'):
import os
code_path = os.getcwd()
data_path = code_path.replace('\\', '/')
data_path = code_path.replace(current_key_word, new_key_word)
if os.path.exists(data_path) == False:
os.makedirs(data_path)
os.chdir(data_path)
def batch_reading_and_plotting(directory, xlabel='x', ylabel='y'):
import re
import os
for root, dirs, files in os.walk(directory):
for file in files:
if re.search('^txt.', file[::-1]):
filename = file[:-4]
x_array, y_array = guan.read_one_dimensional_data(filename=filename)
guan.plot(x_array, y_array, xlabel=xlabel, ylabel=ylabel, title=filename, show=0, save=1, filename=filename)
# Module 13: others
## download
def download_with_scihub(address=None, num=1):
from bs4 import BeautifulSoup
import re
import requests
import os
if num==1 and address!=None:
address_array = [address]
else:
address_array = []
for i in range(num):
address = input('\nInput')
address_array.append(address)
for address in address_array:
r = requests.post('https://sci-hub.st/', data={'request': address})
print('\nResponse', r)
print('Address', r.url)
soup = BeautifulSoup(r.text, features='lxml')
pdf_URL = soup.iframe['src']
if re.search(re.compile('^https:'), pdf_URL):
pass
else:
pdf_URL = 'https:'+pdf_URL
print('PDF address', pdf_URL)
name = re.search(re.compile('fdp.*?/'),pdf_URL[::-1]).group()[::-1][1::]
print('PDF name', name)
print('Directory', os.getcwd())
print('\nDownloading...')
r = requests.get(pdf_URL, stream=True)
with open(name, 'wb') as f:
for chunk in r.iter_content(chunk_size=32):
f.write(chunk)
print('Completed!\n')
if num != 1:
print('All completed!\n')
## audio
def str_to_audio(str='hello world', rate=125, voice=1, read=1, save=0, print_text=0):
import pyttsx3
if print_text==1:
print(str)
engine = pyttsx3.init()
voices = engine.getProperty('voices')
engine.setProperty('voice', voices[voice].id)
engine.setProperty("rate", rate)
if save==1:
engine.save_to_file(str, 'str.mp3')
engine.runAndWait()
print('MP3 file saved!')
if read==1:
engine.say(str)
engine.runAndWait()
def txt_to_audio(txt_path, rate=125, voice=1, read=1, save=0, print_text=0):
import pyttsx3
f = open(txt_path, 'r', encoding ='utf-8')
text = f.read()
if print_text==1:
print(text)
engine = pyttsx3.init()
voices = engine.getProperty('voices')
engine.setProperty('voice', voices[voice].id)
engine.setProperty("rate", rate)
if save==1:
import re
file_name = re.split('[/,\\\]', txt_path)[-1][:-4]
engine.save_to_file(text, file_name+'.mp3')
engine.runAndWait()
print('MP3 file saved!')
if read==1:
engine.say(text)
engine.runAndWait()
def pdf_to_text(pdf_path):
from pdfminer.pdfparser import PDFParser, PDFDocument
from pdfminer.pdfinterp import PDFResourceManager, PDFPageInterpreter
from pdfminer.converter import PDFPageAggregator
from pdfminer.layout import LAParams, LTTextBox
from pdfminer.pdfinterp import PDFTextExtractionNotAllowed
import logging
logging.Logger.propagate = False
logging.getLogger().setLevel(logging.ERROR)
praser = PDFParser(open(pdf_path, 'rb'))
doc = PDFDocument()
praser.set_document(doc)
doc.set_parser(praser)
doc.initialize()
if not doc.is_extractable:
raise PDFTextExtractionNotAllowed
else:
rsrcmgr = PDFResourceManager()
laparams = LAParams()
device = PDFPageAggregator(rsrcmgr, laparams=laparams)
interpreter = PDFPageInterpreter(rsrcmgr, device)
content = ''
for page in doc.get_pages():
interpreter.process_page(page)
layout = device.get_result()
for x in layout:
if isinstance(x, LTTextBox):
content = content + x.get_text().strip()
return content
def pdf_to_audio(pdf_path, rate=125, voice=1, read=1, save=0, print_text=0):
import pyttsx3
text = guan.pdf_to_text(pdf_path)
text = text.replace('\n', ' ')
if print_text==1:
print(text)
engine = pyttsx3.init()
voices = engine.getProperty('voices')
engine.setProperty('voice', voices[voice].id)
engine.setProperty("rate", rate)
if save==1:
import re
file_name = re.split('[/,\\\]', pdf_path)[-1][:-4]
engine.save_to_file(text, file_name+'.mp3')
engine.runAndWait()
print('MP3 file saved!')
if read==1:
engine.say(text)
engine.runAndWait()
def play_academic_words(bre_or_ame='ame', random_on=0, show_translation=1, show_link=1, translation_time=2, rest_time=1):
from bs4 import BeautifulSoup
import re
import urllib.request
import requests
import os
import pygame
import time
import ssl
import random
ssl._create_default_https_context = ssl._create_unverified_context
html = urllib.request.urlopen("https://www.guanjihuan.com/archives/4418").read().decode('utf-8')
if bre_or_ame == 'ame':
directory = 'words_mp3_ameProns/'
elif bre_or_ame == 'bre':
directory = 'words_mp3_breProns/'
exist_directory = os.path.exists(directory)
html_file = urllib.request.urlopen("https://file.guanjihuan.com/words/"+directory).read().decode('utf-8')
if exist_directory == 0:
os.makedirs(directory)
soup = BeautifulSoup(html, features='lxml')
contents = re.findall('<h2>.*?<h2>', html, re.S)
if random_on==1:
random.shuffle(contents)
for content in contents:
soup2 = BeautifulSoup(content, features='lxml')
all_h2 = soup2.find_all('h2')
for h2 in all_h2:
if re.search('\d*. ', h2.get_text()):
word = re.findall('[a-zA-Z].*', h2.get_text(), re.S)[0]
exist = os.path.exists(directory+word+'.mp3')
if not exist:
try:
if re.search(word, html_file):
r = requests.get("https://file.guanjihuan.com/words/"+directory+word+".mp3", stream=True)
with open(directory+word+'.mp3', 'wb') as f:
for chunk in r.iter_content(chunk_size=32):
f.write(chunk)
except:
pass
print(h2.get_text())
if show_link==1:
print('https://www.ldoceonline.com/dictionary/'+word)
try:
pygame.mixer.init()
track = pygame.mixer.music.load(directory+word+'.mp3')
pygame.mixer.music.play()
translation = re.findall('<p>.*?</p>', content, re.S)[0][3:-4]
if show_translation==1:
time.sleep(translation_time)
print(translation)
time.sleep(rest_time)
pygame.mixer.music.stop()
except:
pass
print()