# -*- coding: utf-8 -*- # ------------------------------------------------------------- # Two-probe Configuration # ------------------------------------------------------------- # ------------------------------------------------------------- # Left Electrode # ------------------------------------------------------------- # Set up lattice vector_a = [1.3325, -2.30795770109, 0.0]*Angstrom vector_b = [1.3325, 2.30795770109, 0.0]*Angstrom vector_c = [0.0, 0.0, 4.947]*Angstrom left_electrode_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements left_electrode_elements = [Zinc, Zinc] # Define coordinates left_electrode_coordinates = [[ 1.3325 , 0.76931925, 1.23675 ], [ 1.3325 , -0.76931925, 3.71025 ]]*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 = [1.3325, -2.30795770109, 0.0]*Angstrom vector_b = [1.3325, 2.30795770109, 0.0]*Angstrom vector_c = [0.0, 0.0, 4.947]*Angstrom right_electrode_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements right_electrode_elements = [Zinc, Zinc] # Define coordinates right_electrode_coordinates = [[ 1.0280478 , 0.59354366, 1.23675 ], [ 1.0280478 , -0.94509484, 3.71025 ]]*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 = [1.3325, -2.30795770109, 0.0]*Angstrom vector_b = [1.3325, 2.30795770109, 0.0]*Angstrom vector_c = [0.0, 0.0, 40.5741587317]*Angstrom central_region_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements central_region_elements = [Zinc, Zinc, Zinc, Zinc, Zinc, Zinc, Oxygen, Zinc, Oxygen, Zinc, Oxygen, Zinc, Oxygen, Zinc, Oxygen, Zinc, Zinc, Zinc, Zinc, Zinc, Zinc] # Define coordinates central_region_coordinates = [[ 1.3325 , 0.76931925, 1.23675 ], [ 1.3325 , -0.76931925, 3.71025 ], [ 1.3325 , 0.76931925, 6.18375 ], [ 1.3325 , -0.76931925, 8.65725 ], [ 1.3325 , 0.76931925, 11.13075 ], [ 1.3325 , -0.76931925, 13.60425 ], [ 1.3325 , -0.76931925, 15.60909881], [ 2.3605478 , 0.17577554, 16.27738175], [ 2.3605478 , 0.17577554, 18.28223056], [ 1.0280478 , 0.59354366, 18.95051349], [ 1.0280478 , 0.59354366, 20.9553623 ], [ 1.3325 , -0.76931925, 21.62364524], [ 1.3325 , -0.76931925, 23.62849405], [ 2.3605478 , 0.17577554, 24.29677699], [ 2.3605478 , 0.17577554, 26.3016258 ], [ 1.0280478 , 0.59354366, 26.96990873], [ 1.0280478 , -0.94509484, 29.44340873], [ 1.0280478 , 0.59354366, 31.91690873], [ 1.0280478 , -0.94509484, 34.39040873], [ 1.0280478 , 0.59354366, 36.86390873], [ 1.0280478 , -0.94509484, 39.33740873]]*Angstrom # Set up configuration central_region = BulkConfiguration( bravais_lattice=central_region_lattice, elements=central_region_elements, cartesian_coordinates=central_region_coordinates ) device_configuration = DeviceConfiguration( central_region, [left_electrode, right_electrode], equivalent_electrode_lengths=[4.947, 4.947]*Angstrom, ) # ------------------------------------------------------------- # Calculator # ------------------------------------------------------------- #---------------------------------------- # Hamiltonian Parametrization #---------------------------------------- hamiltonian_parametrization = SlaterKosterHamiltonianParametrization( basis_set=DFTBDirectory("dftb/znorg-0-1/")) #---------------------------------------- # Pair Potentials #---------------------------------------- pair_potentials = DFTBDirectory("dftb/znorg-0-1/") #---------------------------------------- # Numerical Accuracy Settings #---------------------------------------- left_electrode_k_point_sampling = MonkhorstPackGrid( na=5, nb=5, nc=100, ) left_electrode_numerical_accuracy_parameters = NumericalAccuracyParameters( k_point_sampling=left_electrode_k_point_sampling, density_mesh_cutoff=10.0*Hartree, ) right_electrode_k_point_sampling = MonkhorstPackGrid( na=5, nb=5, nc=100, ) right_electrode_numerical_accuracy_parameters = NumericalAccuracyParameters( k_point_sampling=right_electrode_k_point_sampling, density_mesh_cutoff=10.0*Hartree, ) device_k_point_sampling = MonkhorstPackGrid( na=5, nb=5, nc=100, ) device_numerical_accuracy_parameters = NumericalAccuracyParameters( k_point_sampling=device_k_point_sampling, density_mesh_cutoff=10.0*Hartree, ) #---------------------------------------- # Iteration Control Settings #---------------------------------------- left_electrode_iteration_control_parameters = IterationControlParameters() right_electrode_iteration_control_parameters = IterationControlParameters() device_iteration_control_parameters = IterationControlParameters() #---------------------------------------- # Poisson Solver Settings #---------------------------------------- left_electrode_poisson_solver = FastFourier2DSolver( boundary_conditions=[[PeriodicBoundaryCondition(),PeriodicBoundaryCondition()], [PeriodicBoundaryCondition(),PeriodicBoundaryCondition()], [PeriodicBoundaryCondition(),PeriodicBoundaryCondition()]] ) right_electrode_poisson_solver = FastFourier2DSolver( boundary_conditions=[[PeriodicBoundaryCondition(),PeriodicBoundaryCondition()], [PeriodicBoundaryCondition(),PeriodicBoundaryCondition()], [PeriodicBoundaryCondition(),PeriodicBoundaryCondition()]] ) #---------------------------------------- # Electrode Calculators #---------------------------------------- left_electrode_calculator = SemiEmpiricalCalculator( hamiltonian_parametrization=hamiltonian_parametrization, pair_potentials=pair_potentials, numerical_accuracy_parameters=left_electrode_numerical_accuracy_parameters, iteration_control_parameters=left_electrode_iteration_control_parameters, poisson_solver=left_electrode_poisson_solver, ) right_electrode_calculator = SemiEmpiricalCalculator( hamiltonian_parametrization=hamiltonian_parametrization, pair_potentials=pair_potentials, numerical_accuracy_parameters=right_electrode_numerical_accuracy_parameters, iteration_control_parameters=right_electrode_iteration_control_parameters, poisson_solver=right_electrode_poisson_solver, ) #---------------------------------------- # Device Calculator #---------------------------------------- calculator = DeviceSemiEmpiricalCalculator( hamiltonian_parametrization=hamiltonian_parametrization, pair_potentials=pair_potentials, numerical_accuracy_parameters=device_numerical_accuracy_parameters, iteration_control_parameters=device_iteration_control_parameters, electrode_calculators= [left_electrode_calculator, right_electrode_calculator], ) device_configuration.setCalculator(calculator) # ------------------------------------------------------------- # Initial State # ------------------------------------------------------------- old_calculation = nlread('zero-bias.hdf5', DeviceConfiguration)[0] device_configuration.setCalculator( calculator, initial_state=old_calculation, ) nlsave('iv-curve.hdf5', device_configuration) nlprint(device_configuration) # ------------------------------------------------------------- # IV Characteristics # ------------------------------------------------------------- # Kpoint sampling kpoint_grid = MonkhorstPackGrid( na=20, nb=20, ) # Gate-source voltages gate_source_voltages = numpy.linspace(0, 0, 1)*Volt # Drain-source voltages drain_source_voltages = numpy.linspace(0, 1, 5)*Volt # File name. filename = u'iv-curve.hdf5' iv_characteristics = IVCharacteristics( configuration=device_configuration, filename=filename, object_id='ivcharacteristics', gate_regions=[], gate_source_voltages=gate_source_voltages, drain_source_voltages=drain_source_voltages, energies=None, kpoints=kpoint_grid, self_energy_calculator=RecursionSelfEnergy(), energy_zero_parameter=AverageFermiLevel, infinitesimal=1e-06*eV, log_filename_prefix='ivcharacteristics_', number_of_processes_per_task=None, ) iv_characteristics.update()