|  |  |  | @@ -2,7 +2,7 @@ | 
		
	
		
			
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				|  |  |  |  | # With this package, you can calculate band structures, density of states, quantum transport and topological invariant of tight-binding models by invoking the functions you need. Other frequently used functions are also integrated in this package, such as file reading/writing, figure plotting, data processing. | 
		
	
		
			
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				|  |  |  |  | # The current version is guan-0.0.119, updated on August 10, 2022. | 
		
	
		
			
				|  |  |  |  | # The current version is guan-0.0.120, updated on August 12, 2022. | 
		
	
		
			
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				|  |  |  |  | # Installation: pip install --upgrade guan | 
		
	
		
			
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					|  |  |  | @@ -1551,7 +1551,7 @@ def calculate_chern_number_for_square_lattice(hamiltonian_function, precision=10 | 
		
	
		
			
				|  |  |  |  |     chern_number = chern_number/(2*math.pi*1j) | 
		
	
		
			
				|  |  |  |  |     return chern_number | 
		
	
		
			
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				|  |  |  |  | def calculate_chern_number_for_square_lattice_with_Wilson_loop(hamiltonian_function, precision_of_plaquettes=10, precision_of_Wilson_loop=100, print_show=0): | 
		
	
		
			
				|  |  |  |  | def calculate_chern_number_for_square_lattice_with_Wilson_loop(hamiltonian_function, precision_of_plaquettes=20, precision_of_Wilson_loop=5, print_show=0): | 
		
	
		
			
				|  |  |  |  |     delta = 2*math.pi/precision_of_plaquettes | 
		
	
		
			
				|  |  |  |  |     chern_number = 0 | 
		
	
		
			
				|  |  |  |  |     for kx in np.arange(-math.pi, math.pi, delta): | 
		
	
	
		
			
				
					
					|  |  |  | @@ -1592,6 +1592,66 @@ def calculate_chern_number_for_square_lattice_with_Wilson_loop(hamiltonian_funct | 
		
	
		
			
				|  |  |  |  |     chern_number = chern_number/(2*math.pi) | 
		
	
		
			
				|  |  |  |  |     return chern_number | 
		
	
		
			
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				|  |  |  |  | def calculate_chern_number_for_square_lattice_with_Wilson_loop_for_degenerate_case(hamiltonian_function, num_of_bands=[0, 1], precision_of_plaquettes=20, precision_of_Wilson_loop=5, print_show=0): | 
		
	
		
			
				|  |  |  |  |     delta = 2*math.pi/precision_of_plaquettes | 
		
	
		
			
				|  |  |  |  |     chern_number = 0 | 
		
	
		
			
				|  |  |  |  |     for kx in np.arange(-math.pi, math.pi, delta): | 
		
	
		
			
				|  |  |  |  |         if print_show == 1: | 
		
	
		
			
				|  |  |  |  |             print(kx) | 
		
	
		
			
				|  |  |  |  |         for ky in np.arange(-math.pi, math.pi, delta): | 
		
	
		
			
				|  |  |  |  |             vector_array = [] | 
		
	
		
			
				|  |  |  |  |             # line_1 | 
		
	
		
			
				|  |  |  |  |             for i0 in range(precision_of_Wilson_loop): | 
		
	
		
			
				|  |  |  |  |                 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)   | 
		
	
		
			
				|  |  |  |  |                 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, 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): | 
		
	
		
			
				|  |  |  |  |                 H_delta = hamiltonian_function(kx, ky+delta-delta/precision_of_Wilson_loop*i0)   | 
		
	
		
			
				|  |  |  |  |                 eigenvalue, eigenvector = np.linalg.eig(H_delta) | 
		
	
		
			
				|  |  |  |  |                 vector_delta = eigenvector[:, np.argsort(np.real(eigenvalue))] | 
		
	
		
			
				|  |  |  |  |                 vector_array.append(vector_delta)            | 
		
	
		
			
				|  |  |  |  |             Wilson_loop = 1 | 
		
	
		
			
				|  |  |  |  |             dim = len(num_of_bands) | 
		
	
		
			
				|  |  |  |  |             for i0 in range(len(vector_array)-1): | 
		
	
		
			
				|  |  |  |  |                 dot_matrix = np.zeros((dim , dim), dtype=complex) | 
		
	
		
			
				|  |  |  |  |                 i01 = 0 | 
		
	
		
			
				|  |  |  |  |                 for dim1 in num_of_bands: | 
		
	
		
			
				|  |  |  |  |                     i02 = 0 | 
		
	
		
			
				|  |  |  |  |                     for dim2 in num_of_bands: | 
		
	
		
			
				|  |  |  |  |                         dot_matrix[i01, i02] = np.dot(vector_array[i0][:, dim1].transpose().conj(), vector_array[i0+1][:, dim2]) | 
		
	
		
			
				|  |  |  |  |                         i02 += 1 | 
		
	
		
			
				|  |  |  |  |                     i01 += 1 | 
		
	
		
			
				|  |  |  |  |                 det_value = np.linalg.det(dot_matrix) | 
		
	
		
			
				|  |  |  |  |                 Wilson_loop = Wilson_loop*det_value | 
		
	
		
			
				|  |  |  |  |             dot_matrix_plus = np.zeros((dim , dim), dtype=complex) | 
		
	
		
			
				|  |  |  |  |             i01 = 0 | 
		
	
		
			
				|  |  |  |  |             for dim1 in num_of_bands: | 
		
	
		
			
				|  |  |  |  |                 i02 = 0 | 
		
	
		
			
				|  |  |  |  |                 for dim2 in num_of_bands: | 
		
	
		
			
				|  |  |  |  |                     dot_matrix_plus[i01, i02] = np.dot(vector_array[len(vector_array)-1][:, dim1].transpose().conj(), vector_array[0][:, dim2]) | 
		
	
		
			
				|  |  |  |  |                     i02 += 1 | 
		
	
		
			
				|  |  |  |  |                 i01 += 1 | 
		
	
		
			
				|  |  |  |  |             det_value = np.linalg.det(dot_matrix_plus) | 
		
	
		
			
				|  |  |  |  |             Wilson_loop = Wilson_loop*det_value | 
		
	
		
			
				|  |  |  |  |             arg = np.log(Wilson_loop)/1j | 
		
	
		
			
				|  |  |  |  |             chern_number = chern_number + arg | 
		
	
		
			
				|  |  |  |  |     chern_number = chern_number/(2*math.pi) | 
		
	
		
			
				|  |  |  |  |     return chern_number | 
		
	
		
			
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				|  |  |  |  | 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 | 
		
	
	
		
			
				
					
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