Hello everyone, i would appreciate any help you could give me to solve this
issue.
Well, the problem is that i cant find a way to properly show the desired
hopppings in this structure, as you could see i've tried usign the
lat.neighbors() function showing me wrong hoppings and the HoppingKind
function sending a error msg listed below. The hoppings im trying to define
are the ones joining the central atom with the 3 nearest neighbors in the
top layer and the 3 nearest neighbors in the bottom layer.
Im pretty new using kwant so any advice is appreciated.
P.D. Sorry for my bad english
import kwant
from matplotlib import pyplot
VectoresPrimitivos = [(3.176, 0, 0), (1.588, 2.7504, 0), (0, 0, 10)]
base = [(0, 0, 0), (1.588, 0.9168, 0.8745), (0, 0, 1.749)]
lat = kwant.lattice.general(prim_vecs = VectoresPrimitivos, basis = base)
a, b, c= lat.sublattices
def make_cuboid(t=1.0, a=15, b=10, c=5):
def cuboid_shape(pos):
x, y, z = pos
return 0 <= x < a and 0 <= y < b and 0 <= z < c
syst = kwant.Builder()
syst[lat.shape(cuboid_shape, (0, 0, 0))] = 4 * t
#syst[lat.neighbors(3, 1e-07)] = 3
lead = kwant.Builder(kwant.TranslationalSymmetry((-3.176, 0, 0)))
#hoppings = (((1, 0, 0), a, b), ((0, 0, 0), a, b), ((0, 0, 0), c, b),
((-1, 0, 0), c, b))
#syst[[kwant.builder.HoppingKind(*hopping) for hopping in hoppings]] =
-1
def lead_shape(pos):
return 0 <= pos[1] < b and 0 <= pos[2] < c
lead[lat.shape(lead_shape, (0, 0, 0))] = 4 * t
#lead[lat.neighbors(3, 1e-07)] = 3
syst.attach_lead(lead)
syst.attach_lead(lead.reversed())
return syst
def plot_conductance(syst, energies):
data = []
for energy in energies:
smatrix = kwant.smatrix(syst, energy)
data.append(smatrix.transmission(1, 0))
pyplot.figure()
pyplot.plot(energies, data)
pyplot.xlabel("energy [t]")
pyplot.ylabel("conductance [e^2/h]")
pyplot.show()
def main():
syst = make_cuboid()
kwant.plot(syst)
syst = make_cuboid(a=100, b=19, c=4)
def family_colors(site):
if site.family == a:
return 'yellow'
elif site.family == b:
return 'gray'
else:
return 'black'
kwant.plot(syst, site_size=0.25, site_lw=0.025, hop_lw=0.05,
site_color=family_colors)
syst = syst.finalized()
plot_conductance(syst, energies=[0.01 * i - 0.3 for i in range(100)])
def print_hop_kind(hop_kind):
print ('HoppingKind' + hop_kind.delta.__str__() + ', ' +
hop_kind.family_a.name + ', ' + hop_kind.family_b.name )
print ('Nearest neighbors:')
for i in lat.neighbors(3):
print_hop_kind(i)
if __name__ == '__main__':
main()
ERROR MESSAGE
TypeError Traceback (most recent call
last)<ipython-input-54-7d65fe171f23> in <module>() 79 80 if
__name__ == '__main__':---> 81 main()
<ipython-input-54-7d65fe171f23> in main() 48 def main(): 49
---> 50 syst = make_cuboid() 51 kwant.plot(syst) 52
<ipython-input-54-7d65fe171f23> in make_cuboid(t, a, b, c) 21
22 hoppings = (((1, 0, 0), a, b), ((0, 0, 0), a, b), ((0, 0, 0),
c, b), ((-1, 0, 0), c, b))---> 23
syst[[kwant.builder.HoppingKind(*hopping) for hopping in hoppings]] =
-1 24 25 def lead_shape(pos):
<ipython-input-54-7d65fe171f23> in <listcomp>(.0) 21 22
hoppings = (((1, 0, 0), a, b), ((0, 0, 0), a, b), ((0, 0, 0), c, b),
((-1, 0, 0), c, b))---> 23
syst[[kwant.builder.HoppingKind(*hopping) for hopping in hoppings]] =
-1 24 25 def lead_shape(pos):
/usr/lib/python3/dist-packages/kwant/builder.py in __init__(self,
delta, family_a, family_b) 361 def __init__(self, delta,
family_a, family_b=None): 362 self.delta = ta.array(delta,
int)--> 363 ensure_isinstance(family_a, SiteFamily) 364
self.family_a = family_a 365 if family_b is None:
/usr/lib/python3/dist-packages/kwant/_common.py in
ensure_isinstance(obj, typ, msg) 97 if msg is None: 98
msg = "Expecting an instance of {}.".format(typ.__name__)---> 99
raise TypeError(msg)
TypeError: Expecting an instance of SiteFamily.
