def get_bar(param):
g = geometry.square_ribbon(4) # create geometry of the system
#g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system
g = geometry.chain() # create geometry of the system
g.r = np.array([g.r[0]])
g.a1 /= 2
g.r2xyz()
# g = g.supercell(4)
h = g.get_hamiltonian() # create hamiltonian
# h.get_bands()
# exit()
hr = h.copy()
hl = h.copy()
hc = h.copy()
# fermi and pairing
hr.shift_fermi(1.)
hl.shift_fermi(1.)
hc.shift_fermi(1.)
hr.add_swave(param)
hc.add_swave(0.0)
hl.add_swave(0.0)
# of the scattering centrl part
# create a junction object
ht = heterostructures.create_leads_and_central(hr,hl,hc,block_diagonal=False,
num_central = 1)
# hlist = [hc for i in range(80)] # create a list with the hamiltonians
hlist = [hc] # create a list with the hamiltonians
# ht = heterostructures.create_leads_and_central_list(hr,hl,hlist)
# ht.left_coupling *= .2
ht.right_coupling *= .1
return ht
def bulk2ribbon(h,mag_field=0.05,n=10,sparse=True,check=True):
""" Generate the Hamiltonian of a ribbon with magnetic field"""
if not h.is_multicell: # dense hamiltonian
ho = ribbonizate.hamiltonian_bulk2ribbon(h,n=n,sparse=sparse,check=check) # create hamiltonian
else: # sparse hamiltonian
from skeleton import build_ribbon
import geometry
gsk = geometry.square_ribbon(n) # skeleton geometry
ho = build_ribbon(h,g=gsk,n=n) # build the geometry
ho.geometry.center()
if np.abs(mag_field)>0.0000001: ho.add_peierls(mag_field) # add peierls phase
return ho
def get_bar(param):
g = geometry.square_ribbon(4) # create geometry of the system
#g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system
g = geometry.square_ribbon(1) # create geometry of the system
#g = g.supercell(10)
h = g.get_hamiltonian() # create hamiltonian
#h.shift_fermi(0.5)
hr = h.copy()
hl = h.copy()
hc = h.copy()
hc.add_rashba(.6)
hc.add_zeeman([.0, 0., 0.2])
hc.shift_fermi(2.0)
#hc.get_bands()
#exit()
#exit()
hr.shift_fermi(1.)
hl.shift_fermi(1.)
hr.add_swave(0.0)
hc.add_swave(param)
hl.add_swave(0.0)
hc.get_bands()
# of the scattering centrl part
# create a junction object
ht = heterostructures.create_leads_and_central(hr,
hl,
hc,
block_diagonal=False,
num_central=1)
hlist = [hc for i in range(80)] # create a list with the hamiltonians
ht = heterostructures.create_leads_and_central_list(hr, hl, hlist)
ht.left_coupling *= .3
ht.right_coupling *= .3
return ht
def bulk2ribbon(h, mag_field=0.05, n=10, sparse=True, check=True):
""" Generate the Hamiltonian of a ribbon with magnetic field"""
if not h.is_multicell: # dense hamiltonian
ho = ribbonizate.hamiltonian_bulk2ribbon(
h, n=n, sparse=sparse, check=check) # create hamiltonian
else: # sparse hamiltonian
from skeleton import build_ribbon
import geometry
gsk = geometry.square_ribbon(n) # skeleton geometry
ho = build_ribbon(h, g=gsk, n=n) # build the geometry
ho.geometry.center()
if np.abs(mag_field) > 0.0000001:
ho.add_peierls(mag_field) # add peierls phase
return ho
def get_bar(param):
g = geometry.square_ribbon(4) # create geometry of the system
#g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system
g = geometry.square_ribbon(1) # create geometry of the system
#g = g.supercell(10)
h = g.get_hamiltonian() # create hamiltonian
#h.shift_fermi(0.5)
hr = h.copy()
hl = h.copy()
hc = h.copy()
hc.add_rashba(.6)
hc.add_zeeman([.0,0.,0.2])
hc.shift_fermi(2.0)
#hc.get_bands()
#exit()
#exit()
hr.shift_fermi(1.)
hl.shift_fermi(1.)
hr.add_swave(0.0)
hc.add_swave(0.1)
hl.add_swave(0.0)
hc.get_bands()
# of the scattering centrl part
# create a junction object
ht = heterostructures.create_leads_and_central(hr,hl,hc,block_diagonal=False,
num_central = 1)
hlist = [hc for i in range(param)] # create a list with the hamiltonians
ht = heterostructures.create_leads_and_central_list(hr,hl,hlist)
ht.left_coupling *= .3
ht.right_coupling *= .3
return ht
def build_ribbon(h, g=None, n=20):
""" Build a supercell using a certain geometry as skeleton"""
if g is None: # if skeleton not provided
h.geometry.get_lattice_name()
if h.geometry.lattice_name == "square": # square lattice
g = geometry.square_ribbon(n)
else:
raise # not implemented
# now build the hamiltonian
ho = h.copy() # generate hamiltonian
intra = [[None for i in range(len(g.r))] for j in range(len(g.r))]
hoppings = [] # empty list for the hoppings
for i in range(len(g.r)): # loop over positions
intra[i][i] = h.intra # intracell hopping
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
intra[i][j] = multicell.get_tij(h, rij=rij)
ho.intra = csc_matrix(bmat(intra)) # add the intracell matrix
for nn in [-3, -2, -1, 1, 2, 3]: # hopping up to third cells
inter = [[None for i in range(len(g.r))] for j in range(len(g.r))]
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
rij += np.array([nn, 0., 0.]) # add the displacement
inter[i][j] = multicell.get_tij(h, rij=rij)
hopping = multicell.Hopping() # create object
hopping.m = csc_matrix(bmat(inter)) # store matrix
hopping.dir = np.array([nn, 0., 0.]) # store vector
hoppings.append(hopping) # store hopping
gout = g.copy() # copy geometry for the hamiltonian
rs = []
for jr in g.r: # loop over skeleton geometry
for ir in h.geometry.r: # loop over basis
rs.append(ir + jr[0] * h.geometry.a1 + jr[1] * h.geometry.a2)
gout.r = np.array(rs) # store
gout.r2xyz() # update
gout.celldis = h.geometry.a1[0] # this has to be well done
ho.geometry = gout # assign geometry
ho.hopping = hoppings # store the full hoppings list
ho.dimensionality = 1 # one dimensional
ho.is_multicell = True # multicell Hamiltonian
ho.is_sparse = True # sparse Hamiltonian
return ho # return ribbon hamiltonian
def build_ribbon(h,g=None,n=20):
""" Build a supercell using a certain geometry as skeleton"""
if g is None: # if skeleton not provided
h.geometry.get_lattice_name()
if h.geometry.lattice_name=="square": # square lattice
g = geometry.square_ribbon(n)
else: raise # not implemented
# now build the hamiltonian
ho = h.copy() # generate hamiltonian
intra = [[None for i in range(len(g.r))] for j in range(len(g.r))]
hoppings = [] # empty list for the hoppings
for i in range(len(g.r)): # loop over positions
intra[i][i] = h.intra # intracell hopping
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
intra[i][j] = multicell.get_tij(h,rij=rij)
ho.intra = csc_matrix(bmat(intra)) # add the intracell matrix
for nn in [-3,-2,-1,1,2,3]: # hopping up to third cells
inter = [[None for i in range(len(g.r))] for j in range(len(g.r))]
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
rij += np.array([nn,0.,0.]) # add the displacement
inter[i][j] = multicell.get_tij(h,rij=rij)
hopping = multicell.Hopping() # create object
hopping.m = csc_matrix(bmat(inter)) # store matrix
hopping.dir = np.array([nn,0.,0.]) # store vector
hoppings.append(hopping) # store hopping
gout = g.copy() # copy geometry for the hamiltonian
rs = []
for jr in g.r: # loop over skeleton geometry
for ir in h.geometry.r: # loop over basis
rs.append(ir + jr[0]*h.geometry.a1 + jr[1]*h.geometry.a2)
gout.r = np.array(rs) # store
gout.r2xyz() # update
gout.celldis = h.geometry.a1[0] # this has to be well done
ho.geometry = gout # assign geometry
ho.hopping = hoppings # store the full hoppings list
ho.dimensionality = 1 # one dimensional
ho.is_multicell = True # multicell Hamiltonian
ho.is_sparse = True # sparse Hamiltonian
return ho # return ribbon hamiltonian
def get_bar(delta1=0.0, delta2=0.0, phi=0.0, j=0.0, cou=1.0):
g = geometry.square_ribbon(4) # create geometry of the system
#g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system
g = geometry.chain() # create geometry of the system
g.r = np.array([g.r[0]])
g.a1 /= 2
g.r2xyz()
# g = g.supercell(4)
h = g.get_hamiltonian() # create hamiltonian
h.shift_fermi(1.0)
# h.get_bands()
# exit()
hr = h.copy()
hl = h.copy()
hc = h.copy()
hc.add_zeeman([0., 0., j])
# hc.add_rashba(0.2)
# fermi and pairing
# hr.shift_fermi(1.)
# hl.shift_fermi(1.)
# hc.shift_fermi(1.)
hr.add_swave(delta=delta2)
hc.add_swave(delta=0.0)
hl.add_swave(delta=delta1, phi=phi)
# of the scattering centrl part
# create a junction object
ht = heterostructures.create_leads_and_central(hr,
hl,
hc,
block_diagonal=False,
num_central=1)
# hlist = [hc for i in range(80)] # create a list with the hamiltonians
hlist = [hc] # create a list with the hamiltonians
# ht = heterostructures.create_leads_and_central_list(hr,hl,hlist)
# ht.left_coupling *= .2
ht.right_coupling *= cou
return ht
def build_ribbon(hin,g=None,n=20):
""" Build a supercell using a certain geometry as skeleton"""
if g is None: # if skeleton not provided
h.geometry.get_lattice_name()
if h.geometry.lattice_name=="square": # square lattice
g = geometry.square_ribbon(n)
else: raise # not implemented
# now build the hamiltonian
h = hin.copy() # generate hamiltonian
# if the hamiltonian is not multicell, turn it so
if not h.is_multicell: h = multicell.turn_multicell(h)
gin = h.geometry # geometry of the hamiltonian input
# use the same axis
gh = sculpt.rotate_a2b(h.geometry,h.geometry.a1,np.array([0.,1.,0.]))
# if np.abs(h.geometry.a1.dot(h.geometry.a2)) > 0.01: raise # orthogonal
# gh = h.geometry
def normalize(v): # normalize a vector
return v/np.sqrt(v.dot(v))
# get reciprocal vectors
(w1,w2,w3) = sculpt.reciprocal(normalize(gh.a1),normalize(gh.a2))
# exit()
def get_rij(r):
"""Provide a vector r, return this vector expressed in the basis cell"""
i = r.dot(w1) # first projection
j = r.dot(w2) # second projection
i,j = round(i),round(j)
print i,j
return [i,j,0] # return indexes
ho = h.copy() # generate hamiltonian
intra = [[None for i in range(len(g.r))] for j in range(len(g.r))]
hoppings = [] # empty list for the hoppings
for i in range(len(g.r)): # loop over positions
intra[i][i] = h.intra # intracell hopping
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
intra[i][j] = multicell.get_tij(h,rij=get_rij(rij))
ho.intra = csc_matrix(bmat(intra)) # add the intracell matrix
for nn in [-3,-2,-1,1,2,3]: # hopping up to third cells
inter = [[None for i in range(len(g.r))] for j in range(len(g.r))]
print "Next"
for i in range(len(g.r)): # hopping up to third cells
for j in range(len(g.r)): # hopping up to third cells
rij = g.r[i] - g.r[j] # distance between replicas
rij += nn*h.geometry.a1 # add the displacement
if i==j: # for diagonal, at least zeros
mm = multicell.get_tij(h,rij=get_rij(rij))
if mm is None: inter[i][j] = h.intra*0.0 # store zero
else: inter[i][j] = mm # store matrix
else: inter[i][j] = multicell.get_tij(h,rij=get_rij(rij))
hopping = multicell.Hopping() # create object
hopping.m = csc_matrix(bmat(inter)) # store matrix
hopping.dir = np.array([nn,0.,0.]) # store vector
hoppings.append(hopping) # store hopping
gout = g.copy() # copy geometry for the hamiltonian
rs = []
for jr in g.r: # loop over skeleton geometry
for ir in h.geometry.r: # loop over basis
rs.append(ir + jr[0]*h.geometry.a1 + jr[1]*h.geometry.a2)
gout.r = np.array(rs) # store
gout.r2xyz() # update
gout.celldis = h.geometry.a1[0] # this has to be well done
ho.geometry = gout # assign geometry
ho.hopping = hoppings # store the full hoppings list
ho.dimensionality = 1 # one dimensional
ho.is_multicell = True # multicell Hamiltonian
ho.is_sparse = True # sparse Hamiltonian
return ho # return ribbon hamiltonian
import sys
sys.path.append("../../../pygra") # add pygra library
import geometry
import heterostructures
import numpy as np
g = geometry.square_ribbon(3)
h = g.get_hamiltonian()
ht = heterostructures.create_leads_and_central(h, h, h)
h.get_bands() # get bandstructure
es = np.linspace(-1., 1., 50)
ts = [ht.landauer(e) for e in es]
np.savetxt("TRANSPORT.OUT", np.matrix([es, ts]).T)
import geometry # library to create crystal geometries import hamiltonians # library to work with hamiltonians import input_tb90 as in90 import heterostructures import sys import sculpt # to modify the geometry import numpy as np import klist import pylab as py import green g = geometry.square_ribbon(4) h = hamiltonians.hamiltonian(g) # create hamiltonian h.first_neighbors() # create first neighbor hopping #h.set_finite() #h.add_zeeman([0.,0.,-1]) h.remove_spin() dx = -6.0 dy = 6j ne = 100 e1 = np.linspace(dx,dx+dy,ne) e2 = np.linspace(dx+dy,dy,ne) e3 = np.linspace(dy,0.0,ne) e4 = np.linspace(0.0,dx,ne) de1 = dy/ne de2 = -dx/ne de3 = -de1
import geometry # library to create crystal geometries
import hamiltonians # library to work with hamiltonians
import heterostructures
import numpy as np
import klist
import pylab as py
import green
import interactions
g = geometry.square_ribbon(4) # create geometry of the system
g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system
h = g.get_hamiltonian() # create hamiltonian
hr = h.copy()
hl = h.copy()
es = np.linspace(-3., 3., 100) # array with the energies
hlist = [h for i in range(10)] # create a list with the hamiltonians
# of the scattering centrl part
# create a junction object
ht = heterostructures.create_leads_and_central_list(hr, hl, hlist)
ht.block2full()
# calculate transmission
figt = ht.plot_landauer(energy=es, delta=0.00001,
has_eh=h.has_eh) # figure with the transmission
figb = h.plot_bands(nkpoints=300) # figure with the bands
py.show()
import geometry # library to create crystal geometries import numpy as np import heterostructures import matplotlib.pyplot as plt g = geometry.square_ribbon(4) # create geometry of the system #g = geometry.honeycomb_zigzag_ribbon(1) # create geometry of the system g = geometry.square_ribbon(1) # create geometry of the system #g = g.supercell(10) h = g.get_hamiltonian() # create hamiltonian #h.shift_fermi(0.5) hr = h.copy() hl = h.copy() hc = h.copy() hc.add_rashba(.6) hc.add_zeeman([.0,0.,0.2]) hc.shift_fermi(2.0) #hc.get_bands() #exit() #exit() #hr.shift_fermi(1.) hr.add_swave(0.0) hc.add_swave(0.1) hl.add_swave(0.0) hc.get_bands() es = np.linspace(-.2,.2,100) # array with the energies
