def surface(h1,
energies=np.linspace(-1., 1., 100),
operator=None,
delta=0.01,
kpath=None,
hs=None):
"""Get the surface DOS of an interface"""
from scipy.sparse import csc_matrix, bmat
if kpath is None:
if h1.dimensionality == 3:
g2d = h1.geometry.copy() # copy Hamiltonian
import sculpt
g2d = sculpt.set_xy_plane(g2d)
kpath = klist.default(g2d, nk=100)
elif h1.dimensionality == 2:
kpath = [[k, 0., 0.] for k in np.linspace(0., 1., 40)]
else:
raise
fo = open("KDOS.OUT", "w")
fo.write("# k, E, Surface, Bulk\n")
tr = timing.Testimator("KDOS") # generate object
ik = 0
h1 = h1.get_multicell() # multicell Hamiltonian
for k in kpath:
tr.remaining(ik, len(kpath)) # generate object
ik += 1
outs = green.surface_multienergy(h1,
k=k,
energies=energies,
delta=delta,
hs=hs)
for (energy, out) in zip(energies, outs):
# write everything
fo.write(str(ik) + " " + str(energy) + " ")
for g in out: # loop
if operator is None:
d = -g.trace()[0, 0].imag # only the trace
elif callable(operator):
d = operator(g, k=k) # call the operator
else:
d = -(g *
operator).trace()[0, 0].imag # assume it is a matrix
fo.write(str(d) + " ") # write in a file
fo.write("\n") # next line
fo.flush() # flush
fo.close()
def bulkandsurface(h1,
energies=np.linspace(-1., 1., 100),
operator=None,
delta=0.01,
hs=None,
nk=30):
"""Compute the DOS of the bulk and the surface"""
tr = timing.Testimator("KDOS") # generate object
ik = 0
h1 = h1.get_multicell() # multicell Hamiltonian
kpath = [np.random.random(3) for i in range(nk)] # loop
dosout = np.zeros((2, len(energies))) # output DOS
for k in kpath:
tr.remaining(ik, len(kpath)) # generate object
ik += 1
outs = green.surface_multienergy(h1,
k=k,
energies=energies,
delta=delta,
hs=hs)
ie = 0
for (energy, out) in zip(energies, outs): # loop over energies
# compute dos
ig = 0
for g in out: # loop
if operator is None:
d = -g.trace()[0, 0].imag # only the trace
elif callable(operator):
d = operator(g, k=k) # call the operator
else:
d = -(g *
operator).trace()[0, 0].imag # assume it is a matrix
dosout[ig, ie] += d # store
ig += 1 # increase site
ie += 1 # increase energy
# write in file
dosout /= nk # normalize
np.savetxt("DOS_BULK_SURFACE.OUT",
np.matrix([energies, dosout[0], dosout[1]]).T)