# Add the root path of the pygra library
import os ; import sys ; sys.path.append(os.environ['PYGRAROOT'])
# zigzag ribbon
import numpy as np
from pygra import geometry
from pygra import scftypes
from pygra import operators
from scipy.sparse import csc_matrix
g = geometry.chain()
g = geometry.honeycomb_lattice()
#g = geometry.kagome_lattice()
g = g.supercell(3)
h = g.get_hamiltonian() # create hamiltonian of the system
h = h.get_multicell()
h.remove_spin()
mf = np.random.random(h.intra.shape) -.5
mf = np.matrix(mf)
mf = mf + mf.H
scf = scftypes.selfconsistency(h,nkp=1,filling=0.5,g=3.0,
mix=0.9,mf=mf,mode="V")
h = scf.hamiltonian # get the Hamiltonian
h.get_bands() # calculate band structure
from pygra import groundstate
groundstate.hopping(h,nrep=3) # write three replicas
#spectrum.fermi_surface(h)
# Add the root path of the pygra library
import os
import sys
sys.path.append(os.environ['PYGRAROOT'])
# zigzag ribbon
import numpy as np
from pygra import geometry
from pygra import scftypes
from pygra import operators
from scipy.sparse import csc_matrix
g = geometry.chain()
g = geometry.honeycomb_lattice()
#g = geometry.kagome_lattice()
g = g.supercell(3)
h = g.get_hamiltonian() # create hamiltonian of the system
h = h.get_multicell()
h.remove_spin()
mf = np.random.random(h.intra.shape) - .5
mf = np.matrix(mf)
mf = mf + mf.H
scf = scftypes.selfconsistency(h,
nkp=1,
filling=0.5,
g=3.0,
mix=0.9,
mf=mf,
mode="V")
h = scf.hamiltonian # get the Hamiltonian
h.get_bands() # calculate band structure
from pygra import groundstate
# Add the root path of the pygra library import os import sys sys.path.append(os.environ['PYGRAROOT']) # zigzag ribbon from pygra import geometry g = geometry.honeycomb_armchair_ribbon(2) # create geometry of a zigzag ribbon g = geometry.chain(2) # create geometry of a zigzag ribbon g.dimensionality = 0 g.write() h = g.get_hamiltonian() from pygra import ldos ldos.multi_ldos(h, projection="atomic")
# Add the root path of the pygra library
import os ; import sys ; sys.path.append(os.environ['PYGRAROOT'])
from pygra import geometry
from pygra import potentials
import numpy as np
g = geometry.chain(400) # chain
g.dimensionality = 0
vs = np.linspace(0.0,4.0,30) # potentials
# loop over v's
def discard(w):
"""Discard edge wavefunctions"""
w2 = np.abs(w)*np.abs(w) # absolute value
n = len(w)
if np.sum(w2[0:n//10])>0.5 or np.sum(w2[9*n//10:n])>0.5: return False
else: return True
fo = open("LAMBDA_VS_V.OUT","w")
lm = [] # empty array
for v in vs: # loop over strengths of the potential
h = g.get_hamiltonian(has_spin=False) # get the Hamiltonian
fun = potentials.aahf1d(v=v,beta=0.0) # function with the AAH potential
h.add_onsite(fun) # add onsite energies
(es,ls) = h.get_tails(discard=discard) # return the localization length
lm.append(np.mean(ls)) # store
# write in file
# Add the root path of the pygra library
import os ; import sys ; sys.path.append(os.environ['PYGRAROOT'])
# zigzag ribbon
from pygra import geometry
from pygra import scftypes
import numpy as np
# this calculates
g = geometry.chain() # chain geometry
h0 = g.get_hamiltonian() # create hamiltonian of the system
fo = open("STIFFNESS.OUT","w") # open file
for a in np.linspace(0.,1.0,100): # loop over angles, in units of 2pi
h = h0.copy()
h.generate_spin_spiral(vector=[0.,0.,1.],qspiral=[a,0.,0.])
h.add_zeeman([1.0,0.0,0.0])
e = h.get_total_energy(nk=10)
fo.write(str(a)+" "+str(e)+"\n") # write
print(a,e)
fo.close()
# Add the root path of the pygra library
import os ; import sys ; sys.path.append(os.environ['PYGRAROOT'])
from pygra import geometry
from pygra import chi
import numpy as np
n = 100
g = geometry.chain(n) # chain
g.dimensionality = 0
Bs = np.linspace(0.0,3.0,300)
fo = open("SWEEP.OUT","w")
for B in Bs:
def ft(r1,r2):
dr = r1-r2
dr = dr.dot(dr)
if 0.9<dr<1.1: return 0.8*np.cos(r1[0]*B*np.pi) + 1.0
return 0.0
h = g.get_hamiltonian(fun=ft,has_spin=False)
es = np.linspace(0.0,7.0,200)
cout = []
for i in range(10,n-10):
es,cs = chi.chargechi(h,es=es,i=i,j=i)
cout.append(cs)
cs = es*0.0 +0j
for o in cout: cs += o
cs /= len(cout)
for (ie,ic) in zip(es,cs):
fo.write(str(B)+" ")
fo.write(str(ie)+" ")
fo.write(str(abs(ic.imag))+"\n")
# Add the root path of the pygra library
import os
import sys
sys.path.append(os.environ['PYGRAROOT'])
from pygra import geometry
from pygra import potentials
import numpy as np
g = geometry.chain(400) # chain
g.dimensionality = 0
vs = np.linspace(0.0, 4.0, 30) # potentials
# loop over v's
def discard(w):
"""Discard edge wavefunctions"""
w2 = np.abs(w) * np.abs(w) # absolute value
n = len(w)
if np.sum(w2[0:n // 10]) > 0.5 or np.sum(w2[9 * n // 10:n]) > 0.5:
return False
else:
return True
fo = open("LAMBDA_VS_V.OUT", "w")
lm = [] # empty array
for v in vs: # loop over strengths of the potential
h = g.get_hamiltonian(has_spin=False) # get the Hamiltonian
fun = potentials.aahf1d(v=v, beta=0.0) # function with the AAH potential
h.add_onsite(fun) # add onsite energies
# Add the root path of the pygra library import os import sys sys.path.append(os.environ['PYGRAROOT']) from pygra import geometry from pygra import topology from pygra import operators g = geometry.chain() # create geometry of a chain h = g.get_hamiltonian(has_spin=True) # get the Hamiltonian, spinfull h.add_rashba(0.5) # add Rashba SOC h.add_zeeman(0.3) # add Zeeman field h.shift_fermi(2.) # add Zeeman field h.add_swave(0.2) # add swave pairing h.get_bands(operator=operators.get_sy(h))
# Add the root path of the pygra library
import os
import sys
sys.path.append(os.environ['PYGRAROOT'])
# zigzag ribbon
from pygra import geometry
from pygra import scftypes
import numpy as np
# this spin calculates the spin stiffness of an interacting 1d chain
g = geometry.chain() # chain geometry
h0 = g.get_hamiltonian() # create hamiltonian of the system
fo = open("STIFFNESS.OUT", "w") # open file
for a in np.linspace(0., .2, 20): # loop over angles, in units of pi
h = h0.copy()
h.generate_spin_spiral(angle=a, vector=[0., 1., 0.])
scf = scftypes.hubbardscf(h,
filling=0.1,
nkp=100,
g=2.5,
silent=True,
mag=[[0., 0., .1]],
mix=0.9,
maxerror=1e-4)
fo.write(str(a) + " " + str(scf.total_energy) + "\n") # write
print(a, scf.total_energy)
fo.close()
# Add the root path of the pygra library import os ; import sys ; sys.path.append(os.environ['PYGRAROOT']) # zigzag ribbon import numpy as np from pygra import geometry from pygra import topology from pygra import phasediagram g = geometry.chain() # create geometry of a chain def getz2(x1,x2): # calculate the Z2 invariant for certain Zeeman and Rashba h = g.get_hamiltonian(has_spin=True) # get the Hamiltonian, spinfull h.add_rashba(0.5) # add Rashba SOC h.add_zeeman(x1+0.5) # add Zeeman field h.shift_fermi(2.0) # add Zeeman field h.add_swave(x2) # add swave pairing phi = topology.berry_phase(h) # get the berry phase return np.abs(phi/np.pi) # now write the Phase diagram in a file phasediagram.diagram2d(getz2,x=np.linspace(-1,1,20,endpoint=True),y=np.linspace(-1,2.,20,endpoint=True),nite=4)
# Add the root path of the pygra library
import os
import sys
sys.path.append(os.environ['PYGRAROOT'])
from pygra import geometry
from pygra import ldos
import numpy as np
n = 40
w = n / 2. # cutoff for the hopping
g = geometry.chain(n) # chain
g.dimensionality = 0
def ft(n):
def f0(i1, i2):
if abs(i1 - i2) == 1:
i0 = (i1 + i2) / 2.0 / n # average
return np.tanh(4. * i0**2)
else:
return 0.
return f0 # return function
f0 = ft(n) # function
def f(r1, r2):
