from units import *
from calc import *
from param import param
param.createdefault("BFIELD_DIRECTION", 'perp') # 'par', 'lateral'
def _conv_bfield(bfield):
if isscalar(bfield):
if param.BFIELD_DIRECTION == 'perp':
return bfield * array((0.,1.,0.))
elif param.BFIELD_DIRECTION == 'par':
return bfield * array((0.,0.,1.))
elif param.BFIELD_DIRECTION == 'lateral':
return bfield * array((1.,0.,0.))
else:
raise "Error: unknown BFIELD_DIRECTION"
else:
bfield = asarray(bfield)
assert bfield.shape == (3,)
return bfield
def calc_H_int(bfield,H_int_B0,xyz):
assert(shape(H_int_B0)[0] == len(xyz.atoms))
assert(shape(H_int_B0)[1] == len(xyz.atoms))
B_e_hbar = _conv_bfield(bfield) * electron / hbar
if all(B_e_hbar == 0):
return H_int_B0
H_int = H_int_B0.copy()
for i in range(len(xyz.atoms)):
#!/usr/bin/env python
from calc import *
from units import *
from param import param
import xyz
param.createdefault("GRAPHENE_CC_DISTANCE", 1.4226*Angstrom)
param.createdefault("GRAPHITE_INTERLAYER_DISTANCE", 3.34*Angstrom)
def SDOS_armchair_analytic(
E, # in units of gamma
N, # chirality of tube: (N,N)
):
Gs = 0.j
for j in range(1,2*N+1):
X = E**2-sin(j*pi/N)**2
if X < 0:
continue
cos_q = -.5*(cos(j*pi/N) + sign(E)*(X)**.5)
if cos_q**2 > 1:
continue
print cos_q
sin_q = (1-cos_q**2)**.5
Gs += E*(.5+1j*sin_q/(2*cos_q+cos(j*pi/N)))
return -Gs.imag/pi
def armchair(N):
CC_distance = param.GRAPHENE_CC_DISTANCE
from calc import *
from units import *
from param import param
import lead as _lead
import conductor as _conductor
param.createdefault("BFIELD_IN_LEADS", True)
class twoprobe:
def __init__(self,conductor,lead_L,lead_R):
self.energy = None
self.bfield = None
self.conductor = conductor
assert type(lead_L) is list
self.lead_L = lead_L
assert type(lead_R) is list
self.lead_R = lead_R
self.Sigma_L = None
self.Sigma_R = None
def set_energy(self,energy):
if self.energy != energy:
self.energy = energy
for l in self.lead_L:
l.set_energy(energy)
for l in self.lead_R:
l.set_energy(energy)
self.conductor.set_energy(energy)
self.Sigma_L = None
self.Sigma_R = None
from numpy import *
from numpy.linalg import *
import scipy, scipy.linalg
from param import param
from units import *
param.createdefault("LOPEZ_SANCHO_ETA", 1e-5*eV)
param.createdefault("LOPEZ_SANCHO_EPSILON", 1e-4*eV)
param.createdefault("LOPEZ_SANCHO_MAXSTEPS", 100)
class chain:
def __init__(self,H_B0,xyz_chain=None,do_cache=True,S=None):
assert type(H_B0) is list
N = H_B0[0].shape[0]
self.N_orbitals = N
for h_b0 in H_B0:
assert type(h_b0) is matrix
assert h_b0.shape == (N,N)
assert h_b0.dtype == H_B0[0].dtype
self.H = H_B0
self.H_B0 = H_B0
if xyz_chain is not None:
import xyz
assert isinstance(xyz_chain,xyz.chain)
self.xyz = xyz_chain
self.xyz_shifted = [ xyz_chain.shift(xyz_chain.period * i) for i in range(1,len(H_B0)) ]
self.bfield = array((0,0,0))
self.nonorthogonal = (S is not None)
from calc import *
from copy import deepcopy
from param import param
param.createdefault("DISORDER_TYPE", "diagonal")
# param.DISORDER_TYPE = "hopping"
param.createdefault("DO_CALC_CHANNELS", False)
param.createdefault("NO_DISORDER_IN_CONTACTS", False)
class conductor:
def __init__(self,xyz,H_int,H_hop):
N = [ H.shape[0] for H in H_int ]
# N = [ len(x.atoms) for x in xyz ]
assert len(H_int)==len(N)
assert len(H_hop)==len(N)-1
for i in range(len(N)):
assert type(H_int[i]) == type(matrix(()))
assert shape(H_int[i]) == (N[i],N[i])
for i in range(len(N)-1):
assert type(H_hop[i]) == type(matrix(()))
assert shape(H_hop[i]) == (N[i],N[i+1])
self.N = N
if xyz is not None:
assert len(xyz) == len(N)
for i in range(len(N)):
assert len(xyz[i].atoms) == N[i]
self.xyz = xyz
self.H_int_B0 = H_int
self.H_hop_B0 = H_hop
#!/usr/bin/env python
import re
from itertools import count
import xyz, cnt, chain, sheet
from param import param
from units import *
from calc import *
###########################
param.createdefault("GRAPHENE_1STNN_HOPPING", 2.66*eV)
def graphene_1stNN_params(dist):
if dist == 0.0:
return (0.0,1.0)
elif dist < param.GRAPHENE_CC_DISTANCE * 1.1:
return (-gamma,0.0)
else:
return (0.0,0.0)
param.createdefault("GRAPHENE_3RDNN_EPSILON0", -0.28*eV)
param.createdefault("GRAPHENE_3RDNN_GAMMA0", 2.97*eV)
param.createdefault("GRAPHENE_3RDNN_GAMMA1", 0.073*eV)
param.createdefault("GRAPHENE_3RDNN_GAMMA2", 0.33*eV)
param.createdefault("GRAPHENE_3RDNN_S0", 0.073)
param.createdefault("GRAPHENE_3RDNN_S1", 0.018)
param.createdefault("GRAPHENE_3RDNN_S2", 0.026)
