def initialize():
""" Initialize the calculation"""
g = get_geometry2d() # get the geometry
from specialhopping import twisted, twisted_matrix
has_spin = False
h = g.get_hamiltonian(is_sparse=True,
has_spin=has_spin,
is_multicell=False,
mgenerator=twisted_matrix(ti=get("tinter"),
lambi=7.0))
# return h
# h.turn_dense()
h.add_sublattice_imbalance(get("mAB")) # sublattice imbalance
efield = get("interlayer_bias")
def bias(r):
if r[2] < 0.0: return efield
else: return -efield
h.shift_fermi(bias)
if h.has_spin:
h.add_zeeman([get("Bx"), get("By"), get("Bz")]) # Zeeman fields
h.add_rashba(get("rashba")) # Rashba field
h.add_antiferromagnetism(get("mAF")) # AF order
h.add_kane_mele(get("kanemele")) # intrinsic SOC
h.shift_fermi(get("fermi")) # shift fermi energy
if False:
h.add_swave(get("swave"))
if False:
if h.has_eh:
print("SCF not implemented with Nambu")
raise
if False:
custom_scf(h) # create the tb90.in
else:
h.write("hamiltonian.in")
klist.default(g, nk=int(get("nkpoints"))) # write klist
# klist.tr_path(nk=int(get("nkpoints"))) # write klist
return h
# Add the root path of the pygra library
import os
import sys
sys.path.append(os.environ['PYGRAROOT'])
import numpy as np
import specialgeometry
n = 7 # this is a parameter that controls the size of the moire unit cell
g = specialgeometry.twisted_bilayer(n) # get the geometry of the system
# g.r is the list with the positions in the unit cell
# g.a1 is the first lattice vector
# g.a2 is the second lattice vector
# This function will create hoppings in the structure
ti = 0.4 # this is the interlayer hopping (in terms of the intralayer)
from specialhopping import twisted_matrix
h = g.get_hamiltonian(is_sparse=True,
has_spin=False,
is_multicell=True,
mgenerator=twisted_matrix(ti=ti))
hk = h.get_hk_gen() # get Bloch Hamiltonian generator
# hk is a function that given a k point, returns the Bloch Hamiltonian
# The k points are in the interval [0.,1.]
# This method automatically computes the local density of states
h.get_ldos(e=0.0) # e is the energy
# This method automatically computes the bands
#h.get_bands(num_bands=20)
# Add the root path of the pygra library
import os ; import sys ; sys.path.append(os.environ['PYGRAROOT'])
from pygra importgeometry
from pygra importhamiltonians
import numpy as np
import klist
import sculpt
import specialgeometry
g = specialgeometry.twisted_bilayer(5)
g.write()
from specialhopping import twisted_matrix
h = g.get_hamiltonian(is_sparse=True,has_spin=False,is_multicell=False,
mgenerator=twisted_matrix(ti=0.4,lambi=7.0))
#h.turn_spinful()
h.add_haldane(0.05)
h.add_sublattice_imbalance(0.5)
#h.add_kane_mele(0.1)
#h.add_rashba(lambda r: 0.1*np.sign(r[2]))
h.shift_fermi(-0.3)
#h.add_sublattice_imbalance(0.1)
#h.shift_fermi(lambda r: r[2]*0.1)
import density
#h.set_filling(nk=3,extrae=1.) # set to half filling + 2 e
#d = density.density(h,window=0.1,e=0.025)
#h.shift_fermi(-0.4)
#h.turn_sparse()
#h.get_bands(num_bands=20)
#exit()
import topology
#print(h.get_gap())