def simple_superlattice(file):
f = open(file, 'r')
data = yaml.load(f)
f.close()
well_length = spsc_data.LengthValue(data['well_length'], 'nm')
lattice_well_length = spsc_data.LengthValue(data['lattice_well_length'],
'nm')
lattice_barrier_length = spsc_data.LengthValue(
data['lattice_barrier_length'], 'nm')
state = superlattice_well(data['periods_number'], well_length,
lattice_well_length, lattice_barrier_length)
electron_state = state.electron_states[0]
electron_state.mass = electron_state.mass * data['mass']
electron_state.sum_density = spsc_data.DensityValue(
data['density'], "m^-2")
electron_state.static_potential.value = electron_state.static_potential.value * data[
'lattice_amplitude']
lattice_well_length.convert_to("nm")
lattice_barrier_length.convert_to("nm")
delta_layer_index = (data['delta_layer_period'] - 1) * (
lattice_well_length.value + lattice_barrier_length.value) * DOTS_PER_NM + \
lattice_well_length.value * DOTS_PER_NM / 2 + lattice_barrier_length.value * DOTS_PER_NM
delta_layer_index = int(delta_layer_index)
state.static_density.convert_to('m^-2')
state.static_density[delta_layer_index] = data['delta_layer_density']
state.static_density.mirror()
state.electron_states[0].static_potential.meta_info[
'delta_layer_index'] = delta_layer_index
return state
def solve(self, E, solution_start):
self._reset_to_default_units()
E.convert_to(E.units_default)
lattice_potential = spsc_data.Potential(
self.potential[:self.well_start], self.potential.units)
flat_lattice_potential = self._flatten_potential(lattice_potential)
lattice_length = spsc_data.LengthValue(
self.length.value * (len(flat_lattice_potential) - 1) /
(len(self.potential) - 1), self.length.units)
iteration = SolutionIterationFlatPotential(flat_lattice_potential,
self.mass, lattice_length)
lattice_solution = iteration.solve(E, solution_start)
well_solution_start = (lattice_solution[0][-1],
lattice_solution[1][-1])
well_potential = spsc_data.Potential(
self.potential[self.well_start:self.well_end],
self.potential.units)
well_length = spsc_data.LengthValue(
self.length.value * len(well_potential) /
(len(self.potential) - 1), self.length.units)
iteration = SolutionIterationRungeKutt(well_potential, self.mass,
well_length)
well_solution = iteration.solve(E, well_solution_start)
N = len(self.potential)
solution = (spsc_data.WaveFunction(np.zeros(
(N, ))), spsc_data.WaveFunction(np.zeros((N, ))))
solution[0][:len(lattice_solution[0])] = lattice_solution[0]
solution[0][len(lattice_solution[0]) - 1:len(lattice_solution[0]) +
len(well_solution[0]) - 1] = well_solution[0]
solution[1][:len(lattice_solution[1])] = lattice_solution[1]
solution[1][len(lattice_solution[1]) - 1:len(lattice_solution[1]) +
len(well_solution[1]) - 1] = well_solution[1]
return solution
def superlattice_well(periods_num, well_length, lattice_well_length,
lattice_barrier_length):
well_length.convert_to("nm")
lattice_well_length.convert_to("nm")
lattice_barrier_length.convert_to("nm")
state = spsc_core.StateSimple()
electron_state = spsc_core.ElectronStateSimple()
length = spsc_data.LengthValue(0, "nm")
lattice_length = spsc_data.LengthValue(0, "nm")
for i in range(periods_num):
lattice_length += lattice_well_length + lattice_barrier_length
length += lattice_barrier_length * 2 + well_length + lattice_length * 2
potential = spsc_data.Potential(
np.ones((int(lattice_barrier_length.value * DOTS_PER_NM), ),
"float64"), "eV")
next_index = lattice_barrier_length.value * DOTS_PER_NM
for i in range(periods_num):
potential.append(
spsc_data.Potential(
np.zeros((int(lattice_well_length.value * DOTS_PER_NM), ),
"float64"), "eV"))
potential.append(
spsc_data.Potential(
np.ones((int(lattice_barrier_length.value * DOTS_PER_NM), ),
"float64"), "eV"))
next_index += lattice_well_length.value * DOTS_PER_NM + lattice_barrier_length.value * DOTS_PER_NM
meta_info = {
"well_start": int(next_index),
"lattice_bar_width": int(lattice_barrier_length.value * DOTS_PER_NM),
"lattice_well_width": int(lattice_well_length.value * DOTS_PER_NM)
}
potential.append(
spsc_data.Potential(
np.zeros((int(well_length.value * DOTS_PER_NM), ), "float64"),
"eV"))
next_index += well_length.value * DOTS_PER_NM
meta_info["well_end"] = int(next_index)
empty_dots = int(length.value * DOTS_PER_NM) + 1 - len(potential)
potential.append(
spsc_data.Potential(np.zeros((empty_dots, ), "float64"), "eV"))
potential.mirror()
potential.meta_info = meta_info
electron_state.static_potential = potential
electron_state.mass = spsc_data.MassValue(constants.m_e)
electron_state.sum_density = spsc_data.DensityValue(0, "m^-2")
state.electron_states = [electron_state]
state.length = length
state.static_density = spsc_data.Density(
np.zeros((len(potential, )), "float64"), "m^-2")
state.density_potential = spsc_data.Potential(
np.zeros((len(potential, )), "float64"))
return state
def simple_superlattice_diff_mass(file):
f = open(file, 'r')
data = yaml.load(f)
f.close()
well_length = spsc_data.LengthValue(data['well_length'], 'nm')
lattice_well_length = spsc_data.LengthValue(data['lattice_well_length'],
'nm')
lattice_barrier_length = spsc_data.LengthValue(
data['lattice_barrier_length'], 'nm')
state = superlattice_well(data['periods_number'], well_length,
lattice_well_length, lattice_barrier_length)
electron_state = state.electron_states[0]
mass = spsc_data.MassArray(data['barrier_mass'] * np.ones(
(int(lattice_barrier_length.value * DOTS_PER_NM), ), "float64"))
for i in xrange(data['periods_number']):
mass.append(
spsc_data.MassArray(data['well_mass'] * np.ones(
(int(lattice_well_length.value * DOTS_PER_NM), ), "float64")))
mass.append(
spsc_data.MassArray(data['barrier_mass'] * np.ones(
(int(lattice_barrier_length.value * DOTS_PER_NM), ),
"float64")))
mass.append(
spsc_data.MassArray(data['well_mass'] * np.ones(
(int(well_length.value * DOTS_PER_NM), ), "float64")))
empty_dots = len(electron_state.static_potential) - len(mass)
mass.append(spsc_data.MassArray(np.zeros((empty_dots, ), "float64")))
mass = mass * constants.m_e
mass.mirror()
electron_state.mass = mass
electron_state.sum_density = spsc_data.DensityValue(
data['density'], "m^-2")
electron_state.static_potential.value = electron_state.static_potential.value * data[
'lattice_amplitude']
lattice_well_length.convert_to("nm")
lattice_barrier_length.convert_to("nm")
delta_layer_index = (data['delta_layer_period'] - 1) * (
lattice_well_length.value + lattice_barrier_length.value) * DOTS_PER_NM + \
lattice_well_length.value * DOTS_PER_NM / 2 + lattice_barrier_length.value * DOTS_PER_NM
delta_layer_index = int(delta_layer_index)
state.static_density.convert_to('m^-2')
state.static_density[delta_layer_index] = data['delta_layer_density']
state.static_density.mirror()
state.electron_states[0].static_potential.meta_info[
'delta_layer_index'] = delta_layer_index
return state
def x_electrons_superlattice_diff_mass(file):
f = open(file, 'r')
data = yaml.load(f)
f.close()
well_length = spsc_data.LengthValue(data['well_length'], 'nm')
lattice_well_length = spsc_data.LengthValue(data['lattice_well_length'],
'nm')
lattice_barrier_length = spsc_data.LengthValue(
data['lattice_barrier_length'], 'nm')
state = superlattice_well(data['periods_number'], well_length,
lattice_well_length, lattice_barrier_length)
x_electron_state = state.electron_states[0]
x_electron_state.mass = x_electron_state.mass * data['well_mass_x']
x_electron_state.sum_density = spsc_data.DensityValue(0, "m^-2")
x_electron_state.static_potential.value = x_electron_state.static_potential.value - 1
x_electron_state.static_potential.value = x_electron_state.static_potential.value * (
-data['x_lattice_amplitude'])
x_electron_state.static_potential.value = x_electron_state.static_potential.value + data[
'x_lattice_offset']
state = simple_superlattice_diff_mass(file)
# Denote start and end indexes for X-electron solutions
delta_layer_index = state.electron_states[0].static_potential.meta_info[
'delta_layer_index']
delta_layer_offset = 2 * (lattice_well_length.value +
lattice_barrier_length.value) * DOTS_PER_NM
x_solution_start_index = delta_layer_index - delta_layer_offset
if x_solution_start_index < 0:
x_solution_start_index = 0
x_solution_end_index = delta_layer_index + delta_layer_offset
if x_solution_end_index > (len(x_electron_state.static_potential) - 1):
x_solution_end_index = len(x_electron_state.static_potential) - 1
x_electron_state.static_potential.meta_info['x_solution_start'] = int(
x_solution_start_index)
x_electron_state.static_potential.meta_info['x_solution_end'] = int(
x_solution_end_index)
middle_index = (int(x_solution_end_index) -
int(x_solution_start_index)) / 2
middle_index -= (lattice_well_length.value +
lattice_barrier_length.value) / 2 * DOTS_PER_NM
x_electron_state.static_potential.meta_info['middle_index'] = int(
middle_index)
state.electron_states.append(x_electron_state)
return state
def solve(self, E, solution_start):
self._reset_to_default_units()
E.convert_to(E.units_default)
lattice_potential = spsc_data.Potential(
self.potential[:self.well_start], self.potential.units)
flat_lattice_potential = self._flatten_potential(lattice_potential)
lattice_length = spsc_data.LengthValue(
self.length.value * (len(flat_lattice_potential) - 1) /
(len(self.potential) - 1), self.length.units)
lattice_mass = spsc_data.MassArray(
self.mass[:len(flat_lattice_potential)])
# Need this because the last point in the lattice potential is artificial,
# and we need to keep the same mass as it was in the last point.
lattice_mass.value[-1] = lattice_mass.value[-2]
iteration = SolutionIterationFlatPotentialDiffMass(
flat_lattice_potential, lattice_mass, lattice_length)
lattice_solution = iteration.solve(E, solution_start)
well_solution_start = (lattice_solution[0][-1],
lattice_solution[1][-1])
well_potential = spsc_data.Potential(
self.potential[self.well_start:self.well_end],
self.potential.units)
well_length = spsc_data.LengthValue(
self.length.value * len(well_potential) /
(len(self.potential) - 1), self.length.units)
well_mass = spsc_data.MassValue(self.mass.value[self.well_start])
iteration = SolutionIterationRungeKutt(well_potential, well_mass,
well_length)
well_solution = iteration.solve(E, well_solution_start)
N = len(self.potential)
solution = (spsc_data.WaveFunction(np.zeros(
(N, ))), spsc_data.WaveFunction(np.zeros((N, ))))
solution[0][:len(lattice_solution[0])] = lattice_solution[0]
solution[0][len(lattice_solution[0]) - 1:len(lattice_solution[0]) +
len(well_solution[0]) - 1] = well_solution[0]
solution[1][:len(lattice_solution[1])] = lattice_solution[1]
solution[1][len(lattice_solution[1]) - 1:len(lattice_solution[1]) +
len(well_solution[1]) - 1] = well_solution[1]
return solution
def __init__(self, potential, mass, length):
super(SolutionIterationSlopePotential,
self).__init__(potential, mass, length)
self.slope = spsc_data.ElectricFieldValue(0)
self.x0 = spsc_data.LengthValue(0)
self.eps0 = spsc_data.EnergyValue(0)
self._reset_to_default_units()
# Calculate slope
energy_difference = self.potential[SolutionIterationSlopePotential.SLOPE_RESOLUTION_DOTS_NUM - 1] - \
self.potential[0]
energy_difference = spsc_data.EnergyValue(energy_difference)
voltage_difference = energy_difference.value / constants.e
length_piece = self.length.value * (
SolutionIterationSlopePotential.SLOPE_RESOLUTION_DOTS_NUM -
1) / (len(self.potential) - 1)
self.slope.value = voltage_difference / length_piece
self.x0.value = np.power(
constants.h_plank**2 /
(2 * self.mass.value * constants.e * self.slope.value),
float(1) / 3)
self.eps0.value = constants.e * self.slope.value * self.x0.value
def __init__(self):
self.electron_states = []
self.static_density = spsc_data.Density([])
self.density_potential = spsc_data.Potential([])
self.length = spsc_data.LengthValue(0)
