update

Tutorial/9_Chern_number.py

@@ -0,0 +1,18 @@
+import gjh
+import numpy as np
+from math import *
+
+def hamiltonian_function(kx, ky):  # one QAH model with chern number 2
+    t1 = 1.0
+    t2 = 1.0
+    t3 = 0.5
+    m = -1.0
+    hamiltonian = np.zeros((2, 2), dtype=complex)
+    hamiltonian[0, 1] = 2*t1*cos(kx)-1j*2*t1*cos(ky)
+    hamiltonian[1, 0] = 2*t1*cos(kx)+1j*2*t1*cos(ky)
+    hamiltonian[0, 0] = m+2*t3*sin(kx)+2*t3*sin(ky)+2*t2*cos(kx+ky)
+    hamiltonian[1, 1] = -(m+2*t3*sin(kx)+2*t3*sin(ky)+2*t2*cos(kx+ky))
+    return hamiltonian
+
+chern_number = gjh.calculate_chern_number_for_square_lattice(hamiltonian_function, precision=100)
+print(chern_number)