30 lines
1.2 KiB
Python
30 lines
1.2 KiB
Python
"""
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This code is supported by the website: https://www.guanjihuan.com
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The newest version of this code is on the web page: https://www.guanjihuan.com/archives/27656
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"""
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import guan
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import numpy as np
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# one dimensional chain model
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unit_cell = 0
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hopping = 1
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hamiltonian_function = guan.one_dimensional_fourier_transform_with_k(unit_cell, hopping)
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k_array = np.linspace(-np.pi, np.pi, 100)
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eigenvalue_array = guan.calculate_eigenvalue_with_one_parameter(k_array, hamiltonian_function)
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guan.plot(k_array, eigenvalue_array, xlabel='k', ylabel='E', style='k', title='one dimensional chain model')
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# n times band folding
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max_n = 10
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for n in np.arange(2, max_n+1):
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unit_cell = np.zeros((n, n))
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for i0 in range(int(n)):
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for j0 in range(int(n)):
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if abs(i0-j0)==1:
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unit_cell[i0, j0] = 1
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hopping = np.zeros((n, n))
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hopping[0, n-1] = 1
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hamiltonian_function = guan.one_dimensional_fourier_transform_with_k(unit_cell, hopping)
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k_array = np.linspace(-np.pi, np.pi, 100)
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eigenvalue_array = guan.calculate_eigenvalue_with_one_parameter(k_array, hamiltonian_function)
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guan.plot(k_array, eigenvalue_array, xlabel='k', ylabel='E', style='k', title='%i times band folding'%n) |