Create calculation_of_local_currents_with_guan.py

academic_codes/2020.01.03_1_calculation_of_local_currents/calculation_of_local_currents_with_guan.py

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+"""
+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 numpy as np
+import matplotlib.pyplot as plt
+import time
+import guan
+
+def matrix_00(width=10):  # 电极元胞内跃迁，width不赋值时默认为10  
+    h00 = np.zeros((width, width))
+    for width0 in range(width-1):
+        h00[width0, width0+1] = 1
+        h00[width0+1, width0] = 1
+    return h00
+
+
+def matrix_01(width=10):  # 电极元胞间跃迁，width不赋值时默认为10
+    h01 = np.identity(width)
+    return h01
+
+
+def matrix_LC(width=10, length=300):  # 左电极跳到中心区
+    h_LC = np.zeros((width, width*length))
+    for width0 in range(width):
+        h_LC[width0, width0] = 1
+    return h_LC
+
+
+def matrix_CR(width=10, length=300):  # 中心区跳到右电极
+    h_CR = np.zeros((width*length, width))
+    for width0 in range(width):
+        h_CR[width*(length-1)+width0, width0] = 1
+    return h_CR
+
+
+def matrix_center(width=10, length=300):  # 中心区哈密顿量
+    hamiltonian = np.zeros((width*length, width*length))
+    for length0 in range(length-1):
+        for width0 in range(width):
+            hamiltonian[width*length0+width0, width*(length0+1)+width0] = 1  # 长度方向跃迁
+            hamiltonian[width*(length0+1)+width0, width*length0+width0] = 1 
+    for length0 in range(length):
+        for width0 in range(width-1):
+            hamiltonian[width*length0+width0, width*length0+width0+1] = 1  # 宽度方向跃迁
+            hamiltonian[width*length0+width0+1, width*length0+width0] = 1
+    # 中间加势垒
+    for j0 in range(6):
+        for i0 in range(6): 
+            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 = 0
+    width = 60
+    length = 100
+    h00 = matrix_00(width)
+    h01 = matrix_01(width)
+    h_LC = matrix_LC(width, length)
+    h_CR = matrix_CR(width, length)
+    hamiltonian = matrix_center(width, length) 
+    
+    G_n = guan.electron_correlation_function_green_n_for_local_current(fermi_energy, h00, h01, h_LC, h_CR, hamiltonian)
+
+    direction_x = np.zeros((width, length))
+    direction_y = np.zeros((width, length))
+    for length0 in range(length-1):
+        for width0 in range(width):
+            direction_x[width0, length0] = G_n[width*length0+width0, width*(length0+1)+width0]
+    for length0 in range(length):
+        for width0 in range(width-1):
+            direction_y[width0, length0] = G_n[width*length0+width0, width*length0+width0+1]
+
+    X, Y = np.meshgrid(range(length), range(width))
+    plt.quiver(X, Y, direction_x, direction_y)
+    plt.show()
+    end_time = time.time()
+    print('运行时间=', end_time-start_time)
+
+
+if __name__ == '__main__':
+    main()