def operator_berry(hin,k=[0.,0.],operator=None,delta=0.00001,ewindow=None): """Calculates the Berry curvature using an arbitrary operator""" h = multicell.turn_multicell(hin) # turn to multicell form dhdx = multicell.derivative(h,k,order=[1,0]) # derivative dhdy = multicell.derivative(h,k,order=[0,1]) # derivative hkgen = h.get_hk_gen() # get generator hk = hkgen(k) # get hamiltonian (es,ws) = lg.eigh(hkgen(k)) # initial waves ws = np.conjugate(np.transpose(ws)) # transpose the waves n = len(es) # number of energies from berry_curvaturef90 import berry_curvature as bc90 if operator is None: operator = np.identity(dhdx.shape[0],dtype=np.complex) b = bc90(dhdx,dhdy,ws,es,operator,delta) # berry curvature return b*np.pi*np.pi*8 # normalize so the sum is 2pi Chern
def operator_berry(hin,
k=[0., 0.],
operator=None,
delta=0.00001,
ewindow=None):
"""Calculates the Berry curvature using an arbitrary operator"""
h = multicell.turn_multicell(hin) # turn to multicell form
dhdx = multicell.derivative(h, k, order=[1, 0]) # derivative
dhdy = multicell.derivative(h, k, order=[0, 1]) # derivative
hkgen = h.get_hk_gen() # get generator
hk = hkgen(k) # get hamiltonian
(es, ws) = lg.eigh(hkgen(k)) # initial waves
ws = np.conjugate(np.transpose(ws)) # transpose the waves
n = len(es) # number of energies
from berry_curvaturef90 import berry_curvature as bc90
if operator is None:
operator = np.identity(dhdx.shape[0], dtype=np.complex)
b = bc90(dhdx, dhdy, ws, es, operator, delta) # berry curvature
return b * np.pi * np.pi * 8 # normalize so the sum is 2pi Chern