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Messages - Kenta

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1
General Questions and Answers / Building Quantum well structure
« on: June 4, 2021, 04:29 »
I would like to build a GaAs/Al0.3Ga0.7As quantum well.
Can you tell me how to make the quantum well structure?

2
General Questions and Answers / single electron transistor
« on: December 15, 2020, 05:33 »
I have done that tutorial and the Quantum wise tutorial "Benzene Single-Electron Transistor".
I created  SET device using those and Questions and Answers "Topic: Gate ineffective in tunnel junction device, ? .You can find the code below. Please check it.

Now, I have 5 questions.
1、Does the device I made work as a SET?
2. I have made gold electrodes appropriately, but do the electrodes change the characteristics of the device? If you don't mind, can you tell me how to make suitable electrodes?
3. In my device, the gate voltage is applied only to the center of the device, but should there be gate voltage under the gold electrodes as well?
4,Also, in the case of SETs, I think they work at low temperatures, but by lowering the temperature of the electrodes, does that mean that the temperature of the device is lowered?
5、Do you think about many-body effects in Quantum ATK? Is Coulomb blanket considered when calculating the device? Finally, I would like to see the IV characteristics of SETs and their respective capacitances.

Thank you for your time.
Code
# -*- coding: utf-8 -*-
# -------------------------------------------------------------
# Two-probe Configuration
# -------------------------------------------------------------

# -------------------------------------------------------------
# Left Electrode
# -------------------------------------------------------------

# Set up lattice
vector_a = [12.0, 0.0, 0.0]*Angstrom
vector_b = [0.0, 12.0, 0.0]*Angstrom
vector_c = [0.0, 0.0, 5.88171421]*Angstrom
left_electrode_lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
left_electrode_elements = [Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold,
                           Gold]

# Define coordinates
left_electrode_coordinates = [[ 5.89496938918 ,  6.369816335081,  0.735242827216],
                              [ 5.89496938918 ,  9.310673438036,  0.735242827216],
                              [ 3.81546938918 ,  4.899387783604,  2.205671378694],
                              [ 3.81546938918 ,  7.840244886558,  2.205671378694],
                              [ 7.97446938918 ,  4.899387783604,  2.205671378694],
                              [ 7.97446938918 ,  7.840244886559,  2.205671378694],
                              [ 5.89496938918 ,  6.369816335081,  3.676099930171],
                              [ 5.89496938918 ,  9.310673438036,  3.676099930171],
                              [ 7.97446938918 ,  4.899387783604,  5.146528481649],
                              [ 7.97446938918 ,  7.840244886558,  5.146528481649],
                              [ 3.81546938918 ,  4.899387783604,  5.146528481649],
                              [ 3.81546938918 ,  7.840244886558,  5.146528481648]]*Angstrom

# Set up configuration
left_electrode = BulkConfiguration(
    bravais_lattice=left_electrode_lattice,
    elements=left_electrode_elements,
    cartesian_coordinates=left_electrode_coordinates
    )

# -------------------------------------------------------------
# Right Electrode
# -------------------------------------------------------------

# Set up lattice
vector_a = [12.0, 0.0, 0.0]*Angstrom
vector_b = [0.0, 12.0, 0.0]*Angstrom
vector_c = [0.0, 0.0, 5.88171421]*Angstrom
right_electrode_lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
right_electrode_elements = [Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold,
                            Gold]

# Define coordinates
right_electrode_coordinates = [[ 7.97447       ,  4.899387172784,  0.735185728352],
                               [ 7.97447       ,  7.840244275739,  0.735185728352],
                               [ 3.81547       ,  4.899387172784,  0.735185728352],
                               [ 3.81547       ,  7.840244275739,  0.735185728352],
                               [ 5.89497       ,  9.310672827216,  2.205614279829],
                               [ 5.89497       ,  6.369815724261,  2.205614279829],
                               [ 7.97447       ,  7.840244275739,  3.676042831306],
                               [ 3.81547       ,  7.840244275739,  3.676042831306],
                               [ 7.97447       ,  4.899387172784,  3.676042831306],
                               [ 3.81547       ,  4.899387172784,  3.676042831306],
                               [ 5.89497       ,  9.310672827216,  5.146471382784],
                               [ 5.89497       ,  6.369815724261,  5.146471382784]]*Angstrom

# Set up configuration
right_electrode = BulkConfiguration(
    bravais_lattice=right_electrode_lattice,
    elements=right_electrode_elements,
    cartesian_coordinates=right_electrode_coordinates
    )

# -------------------------------------------------------------
# Central Region
# -------------------------------------------------------------

# Set up lattice
vector_a = [12.0, 0.0, 0.0]*Angstrom
vector_b = [0.0, 12.0, 0.0]*Angstrom
vector_c = [0.0, 0.0, 25.233928324954178]*Angstrom
central_region_lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
central_region_elements = [Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold,
                           Gold, Hydrogen, Carbon, Hydrogen, Hydrogen, Carbon, Carbon, Carbon,
                           Carbon, Hydrogen, Hydrogen, Carbon, Hydrogen, Gold, Gold, Gold,
                           Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold, Gold]

# Define coordinates
central_region_coordinates = [[  5.89496938918 ,   6.369816335081,   0.735242827216],
                              [  5.89496938918 ,   9.310673438036,   0.735242827216],
                              [  3.81546938918 ,   4.899387783604,   2.205671378694],
                              [  3.81546938918 ,   7.840244886558,   2.205671378694],
                              [  7.97446938918 ,   4.899387783604,   2.205671378694],
                              [  7.97446938918 ,   7.840244886559,   2.205671378694],
                              [  5.89496938918 ,   6.369816335081,   3.676099930171],
                              [  5.89496938918 ,   9.310673438036,   3.676099930171],
                              [  7.97446938918 ,   4.899387783604,   5.146528481649],
                              [  7.97446938918 ,   7.840244886558,   5.146528481649],
                              [  3.81546938918 ,   4.899387783604,   5.146528481649],
                              [  3.81546938918 ,   7.840244886558,   5.146528481648],
                              [  5.979528      ,   5.8978735     ,  10.133376813333],
                              [  5.98854       ,   5.9427995     ,  11.227117813333],
                              [  8.139325      ,   6.0629885     ,  11.352576813333],
                              [  3.840072      ,   5.8348215     ,  11.397538813333],
                              [  7.197288      ,   6.0352055     ,  11.909501813333],
                              [  4.791217      ,   5.9075385     ,  11.934521813333],
                              [  7.208723      ,   6.0924095     ,  13.299424813333],
                              [  4.802674      ,   5.9647895     ,  13.324419813333],
                              [  8.159928      ,   6.1651785     ,  13.836366813333],
                              [  3.860514      ,   5.9371685     ,  13.881070813333],
                              [  6.011398      ,   6.0571905     ,  14.006834813333],
                              [  6.020461      ,   6.1022335     ,  15.100537813333],
                              [  7.97447       ,   4.899387172784,  20.087399843306],
                              [  7.97447       ,   7.840244275739,  20.087399843306],
                              [  3.81547       ,   4.899387172784,  20.087399843306],
                              [  3.81547       ,   7.840244275739,  20.087399843306],
                              [  5.89497       ,   9.310672827216,  21.557828394783],
                              [  5.89497       ,   6.369815724261,  21.557828394783],
                              [  7.97447       ,   7.840244275739,  23.02825694626 ],
                              [  3.81547       ,   7.840244275739,  23.02825694626 ],
                              [  7.97447       ,   4.899387172784,  23.02825694626 ],
                              [  3.81547       ,   4.899387172784,  23.02825694626 ],
                              [  5.89497       ,   9.310672827216,  24.498685497738],
                              [  5.89497       ,   6.369815724261,  24.498685497738]]*Angstrom

# Set up configuration
central_region = BulkConfiguration(
    bravais_lattice=central_region_lattice,
    elements=central_region_elements,
    cartesian_coordinates=central_region_coordinates
    )

# Add metallic region
metallic_region_0 = BoxRegion(
    4.0*Volt,
    xmin = 0.0*Angstrom, xmax = 12.0*Angstrom,
    ymin = 0.0*Angstrom, ymax = 1.0*Angstrom,
    zmin = 6.61695731333*Angstrom, zmax = 18.6169573133*Angstrom,
)

metallic_regions = [metallic_region_0]
central_region.setMetallicRegions(metallic_regions)

# Add dielectric region
dielectric_region_0 = BoxRegion(
    10.0,
    xmin = 0.0*Angstrom, xmax = 12.0*Angstrom,
    ymin = 1.0*Angstrom, ymax = 4.7*Angstrom,
    zmin = 6.61695731333*Angstrom, zmax = 18.6169573133*Angstrom,
)

dielectric_regions = [dielectric_region_0]
central_region.setDielectricRegions(dielectric_regions)

device_configuration = DeviceConfiguration(
    central_region,
    [left_electrode, right_electrode],
    equivalent_electrode_lengths=[5.88171421, 5.88171421]*Angstrom,
    transverse_electrode_repetitions=[[1, 1], [1, 1]],
    )

# -------------------------------------------------------------
# Calculator
# -------------------------------------------------------------
#----------------------------------------
# Basis Set
#----------------------------------------
basis_set = [
    LDABasis.Hydrogen_DoubleZetaPolarized,
    LDABasis.Carbon_DoubleZetaPolarized,
    LDABasis.Gold_SingleZetaPolarized,
    ]

#----------------------------------------
# Exchange-Correlation
#----------------------------------------
exchange_correlation = LDA.PZ

#----------------------------------------
# Numerical Accuracy Settings
#----------------------------------------
device_k_point_sampling = KpointDensity(
    density_c=150.0*Angstrom,
    )
device_numerical_accuracy_parameters = NumericalAccuracyParameters(
    k_point_sampling=device_k_point_sampling,
    density_mesh_cutoff=75.0*Hartree,
    )

#----------------------------------------
# Poisson Solver Settings
#----------------------------------------
device_poisson_solver = MultigridSolver(
    boundary_conditions=[[NeumannBoundaryCondition(),NeumannBoundaryCondition()],
                         [NeumannBoundaryCondition(),NeumannBoundaryCondition()],
                         [DirichletBoundaryCondition(),DirichletBoundaryCondition()]]
    )

#----------------------------------------
# Contour Integral Settings
#----------------------------------------
equilibrium_contour = SemiCircleContour(
    integral_lower_bound=1.87054058324*Hartree,
    circle_points=30,
    )
contour_parameters = ContourParameters(
    equilibrium_contour=equilibrium_contour,
    )

#----------------------------------------
# Device Calculator
#----------------------------------------
calculator = DeviceLCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    numerical_accuracy_parameters=device_numerical_accuracy_parameters,
    poisson_solver=device_poisson_solver,
    contour_parameters=contour_parameters,
    )

device_configuration.setCalculator(calculator)
nlprint(device_configuration)
device_configuration.update()
nlsave('1208 prototype device1.hdf5', device_configuration)

# -------------------------------------------------------------
# Device Density Of States
# -------------------------------------------------------------
kpoint_grid = MonkhorstPackGrid()

device_density_of_states = DeviceDensityOfStates(
    configuration=device_configuration,
    energies=numpy.linspace(-2,2,101)*eV,
    kpoints=kpoint_grid,
    contributions=All,
    energy_zero_parameter=AverageFermiLevel,
    infinitesimal=1e-06*eV,
    self_energy_calculator=RecursionSelfEnergy(storage_strategy=NoStorage()),
    )
nlsave('1208 prototype device1.hdf5', device_density_of_states)
nlprint(device_density_of_states)

# -------------------------------------------------------------
# Molecular Energy Spectrum
# -------------------------------------------------------------
molecular_energy_spectrum = MolecularEnergySpectrum(
    configuration=device_configuration,
    energy_zero_parameter=FermiLevel,
    projection_list=ProjectionList(elements=[Carbon, Hydrogen])
    )
nlsave('1208 prototype device1.hdf5', molecular_energy_spectrum)
nlprint(molecular_energy_spectrum)

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