update

academic_codes/2020.01.03_1_calculation_of_local_currents/calculation_of_local_currents.py

@@ -48,13 +48,13 @@ def matrix_center(width=10, length=300):  # 中心区哈密顿量
     # 中间加势垒
     for j0 in range(6):
         for i0 in range(6): 
-            hamiltonian[width*(np.int(length/2)-3+j0)+np.int(width/2)-3+i0, width*(np.int(length/2)-3+j0)+np.int(width/2)-3+i0]= 1e8
+            hamiltonian[width*(int(length/2)-3+j0)+int(width/2)-3+i0, width*(int(length/2)-3+j0)+int(width/2)-3+i0]= 1e8
     return hamiltonian
 
 
 def main():
     start_time = time.time()
-    fermi_energy = 1
+    fermi_energy = 0
     width = 60
     length = 100
     h00 = matrix_00(width)

academic_codes/2020.01.03_1_calculation_of_local_currents/calculation_of_local_currents_with_Kwant.py

@@ -0,0 +1,46 @@
+"""
+This code is supported by the website: https://www.guanjihuan.com
+The newest version of this code is on the web page: https://www.guanjihuan.com/archives/3888
+"""
+
+import kwant
+
+
+def make_system():
+    a = 1
+    lat = kwant.lattice.square(a, norbs=1)  # 创建晶格，方格子
+    syst = kwant.Builder() 
+    t = 1.0
+    W = 60  # 中心体系宽度
+    L = 100  # 中心体系长度
+    # 给中心体系赋值
+    for i in range(L):
+        for j in range(W):
+            syst[lat(i, j)] = 0
+            if j > 0:
+                syst[lat(i, j), lat(i, j-1)] = -t  # hopping in y-direction
+            if i > 0:
+                syst[lat(i, j), lat(i-1, j)] = -t  # hopping in x-direction
+            if 47<=i<53 and 27<=j<33:  # 势垒
+                syst[lat(i, j)] = 1e8
+    # 电极
+    lead = kwant.Builder(kwant.TranslationalSymmetry((-a, 0)))
+    lead[(lat(0, j) for j in range(W))] = 0
+    lead[lat.neighbors()] = -t  # 用neighbors()方法
+    syst.attach_lead(lead)  # 左电极
+    syst.attach_lead(lead.reversed())   # 用reversed()方法得到右电极
+    # 制作结束
+    kwant.plot(syst) 
+    syst = syst.finalized()  
+    return syst
+
+
+def main():
+    syst = make_system()
+    psi = kwant.wave_function(syst)(0)[29]
+    current = kwant.operator.Current(syst)(psi)
+    kwant.plotter.current(syst, current)
+
+
+if __name__ == '__main__':
+    main()