# ------------------------------------------------------------- # Left electrode # ------------------------------------------------------------- # Set up lattice vector_a = [6.0, 0.0, 0.0]*Angstrom vector_b = [0.0, 6.0, 0.0]*Angstrom vector_c = [0.0, 0.0, 5.8]*Angstrom left_electrode_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements left_electrode_elements = [Carbon, Carbon] # Define coordinates left_electrode_coordinates = [[ 3. , 3. , 1.45], [ 3. , 3. , 4.35]]*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 = [6.0, 0.0, 0.0]*Angstrom vector_b = [0.0, 6.0, 0.0]*Angstrom vector_c = [0.0, 0.0, 5.8]*Angstrom right_electrode_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements right_electrode_elements = [Carbon, Carbon] # Define coordinates right_electrode_coordinates = [[ 3. , 3. , 1.45], [ 3. , 3. , 4.35]]*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 = [6.0, 0.0, 0.0]*Angstrom vector_b = [0.0, 6.0, 0.0]*Angstrom vector_c = [0.0, 0.0, 71.5]*Angstrom central_region_lattice = UnitCell(vector_a, vector_b, vector_c) # Define elements central_region_elements = [Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon, Carbon] # Define coordinates central_region_coordinates = [[ 3. , 3. , 1.45], [ 3. , 3. , 4.35], [ 3. , 3. , 7.25], [ 3. , 3. , 10.15], [ 3. , 3. , 13.05], [ 3. , 3. , 15.95], [ 3. , 3. , 18.85], [ 3. , 3. , 21.75], [ 3. , 3. , 24.65], [ 3. , 3. , 27.55], [ 3. , 3. , 30.45], [ 3. , 3. , 33.35], [ 3. , 3. , 38.15], [ 3. , 3. , 41.05], [ 3. , 3. , 43.95], [ 3. , 3. , 46.85], [ 3. , 3. , 49.75], [ 3. , 3. , 52.65], [ 3. , 3. , 55.55], [ 3. , 3. , 58.45], [ 3. , 3. , 61.35], [ 3. , 3. , 64.25], [ 3. , 3. , 67.15], [ 3. , 3. , 70.05]]*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] ) # ------------------------------------------------------------- # Calculator # ------------------------------------------------------------- #---------------------------------------- # Basis Set #---------------------------------------- basis_set = [ LDABasis.Carbon_SingleZeta, ] #---------------------------------------- # Exchange-Correlation #---------------------------------------- exchange_correlation = NCLDA.PZ #---------------------------------------- # 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]] ) # Use the special noncollinear mixing scheme iteration_control_parameters = IterationControlParameters( algorithm=PulayMixer(noncollinear_mixing=True) ) #---------------------------------------- # Electrode Calculators #---------------------------------------- left_electrode_calculator = LCAOCalculator( basis_set=basis_set, exchange_correlation=exchange_correlation, poisson_solver=left_electrode_poisson_solver, ) right_electrode_calculator = LCAOCalculator( basis_set=basis_set, exchange_correlation=exchange_correlation, poisson_solver=right_electrode_poisson_solver, ) #---------------------------------------- # Device Calculator #---------------------------------------- calculator = DeviceLCAOCalculator( basis_set=basis_set, exchange_correlation=exchange_correlation, iteration_control_parameters = iteration_control_parameters, electrode_calculators= [left_electrode_calculator, right_electrode_calculator], ) # Define the spin rotation theta = 90*Degrees left_spins = [(i, 1, 0*Degrees, 0*Degrees) for i in range(12)] right_spins = [(i, 1, theta, 0*Degrees ) for i in range(12,24)] spin_list = left_spins+right_spins initial_spin = InitialSpin(scaled_spins=spin_list) # Setup the initial state device_configuration.setCalculator( calculator, initial_spin=initial_spin, ) # Calculate and save device_configuration.update() nlsave("STT.nc", device_configuration) # ------------------------------------------------------------- # Mulliken population # ------------------------------------------------------------- mulliken_population = MullikenPopulation(device_configuration) nlsave("STT.nc", mulliken_population) nlprint(mulliken_population) #---------------------------------------- # Spin Transfer Torque #---------------------------------------- spin_transfer_torque = SpinTransferTorque( configuration=device_configuration, energy=0.0*eV, kpoints=MonkhorstPackGrid(1,1), contributions=Left, self_energy_calculator=RecursionSelfEnergy(), energy_zero_parameter=AverageFermiLevel, infinitesimal=1.0e-6*eV ) nlsave("STT.nc", spin_transfer_torque)