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Messages - ATK-user-zuox

Pages: [1] 2
1
Dear Quantumwisestaffs:
           Recently i decided to calculate heterojunctions, i learned from post http://quantumwise.com/forum/index.php?topic=4038.msg18443#msg18443that the NeutralAtoms option should be used for the heterogeneous system, but what confused me most is that the phrase in the Atomistix ToolKit Reference Manual"Length over which the atoms in the electrode copy within the central region will be initialized with a linear combination of the converged density matrix of the electrodes and the equivalent bulk density matrix. The weight of the electrode density matrix is 1 at the boundary and 0 at the distance electrode_constraint length from the boundary"from http://www.quantumwise.com/documents/manuals/ATK-2015/ReferenceManual/index.html/ref.neutralatom.html.
            The question is that since the  equivalent bulk is replaced by NeutralAtoms for heterojunctions, why the equivalent bulk calculation  is still involved to get the  equivalent bulk density matrix before the first device electronic convergence. On the other hand, how should we pick appropriate electrode_constraint _length for NeutralAtoms option, or how the magnitude of electrode_constraint_length influence the speed for the subsequent device eletronic convergence. for example, convergence speed will be accelerated if we use the electrode length in the Z direction or just set zero value for electrode_constraint_length?

2
           Recently i  did  the MPSH and calculated the correspponding FMO of the eigenstate.Then i exported  the cube of the FMO.In my opinion ,if  i  want to compare the expansibility of two FMO ,we should square the absolute cube and normalize the squared  cube .So i pick the fourth option,but i can not figure out  if it is normalied? Here is export picture of the FMO.

3
I used my original job and found that my change of
Code
#----------------------------------------
# Iteration Control Settings
#----------------------------------------
left_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=1000,
    )

right_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=1000,
    )

device_iteration_control_parameters = IterationControlParameters(
    damping_factor=0.36,
    max_steps=2000,
    number_of_history_steps=8,
    )
is effective in my calculation and  my calculation accelerates to convergence because of the large damping_factor ,but the  max_steps is not changed .so i am quite confused .As you said , if i  redefine the  Iteration Control Settings in the I-V block ,will it be effective on the max_steps?
Code
# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
#----------------------------------------
# Iteration Control Settings
#----------------------------------------
left_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=3000,
    )

right_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=3000,
    )

device_iteration_control_parameters = IterationControlParameters(
    damping_factor=0.25,
    max_steps=3000,
    number_of_history_steps=12,
    )

calculator=device_configuration.calculator()

biases = [-0.200000, -0.300000, -0.400000, -0.500000,
          -0.600000, -0.700000, -0.800000, -0.900000, -1.000000]*Volt
for bias in biases:
    calculator=calculator(
            electrode_voltages=(bias/2, -bias/2))

    device_configuration.setCalculator(
          calculator(),
          initial_state=device_configuration)
    device_configuration.update()
    nlsave("ivcurve_selfconsistent_configurations_bias_%g.nc" % bias.inUnitsOf(Volt), device_configuration)

4
Dear quantumwise staff:
          Recently i confronted a convergence problems in MoS2 ,so i referred to the forum  and increase the max steps ,the problem is as follows:
if i don't restart from the convergened state ,that is i calculate it from zero bias ,here is my max steps setting.
Code
#----------------------------------------
# Iteration Control Settings
#----------------------------------------
left_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=500,
    )

right_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=500,
    )

device_iteration_control_parameters = IterationControlParameters(
    damping_factor=0.31,
    max_steps=2000,
    number_of_history_steps=10,
    )

#----------------------------------------
# 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]]
    )

#----------------------------------------
# Contour Integral Settings
#----------------------------------------
contour_parameters = DoubleContourIntegralParameters(
    real_axis_infinitesimal=1e-06*Rydberg,
    real_axis_point_density=0.02*eV,
    integral_lower_bound=50.0*eV,
    )

#----------------------------------------
# Electrode Calculators
#----------------------------------------
left_electrode_calculator = LCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=left_electrode_iteration_control_parameters,
    poisson_solver=left_electrode_poisson_solver,
    )

right_electrode_calculator = LCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=right_electrode_iteration_control_parameters,
    poisson_solver=right_electrode_poisson_solver,
    )

#----------------------------------------
# Device Calculator
#----------------------------------------
calculator = DeviceLCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=device_iteration_control_parameters,
    contour_parameters=contour_parameters,
    electrode_calculators=
        [left_electrode_calculator, right_electrode_calculator],
    )

device_configuration.setCalculator(calculator)

# -------------------------------------------------------------
# Initial State
# -------------------------------------------------------------
initial_spin = InitialSpin(scaled_spins=[0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, -1.0, -1.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, -1.0, 0.0, -1.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0, 0.0, 0.0, -1.0, -1.0, 0.0, 0.0, 0.0, -1.0, 0.0, 0.0, -1.0, 0.0, -1.0, 0.0, 0.0])
device_configuration.setCalculator(
    calculator,
    initial_spin=initial_spin,
)
device_configuration.update()
nlsave('CONFIG.nc', device_configuration)
nlprint(device_configuration)

# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
calculator=device_configuration.calculator()

biases = [0.100000, 0.200000, 0.300000, 0.400000, 0.500000,
          0.600000, 0.700000, 0.800000, 0.900000, 1.000000]*Volt
for bias in biases:
    calculator=calculator(
            electrode_voltages=(bias/2, -bias/2))

    device_configuration.setCalculator(
          calculator(),
          initial_state=device_configuration)
    device_configuration.update()
    nlsave("ivcurve_selfconsistent_configurations_bias_%g.nc" % bias.inUnitsOf(Volt), device_configuration)
My calculation is slowly converged in the step =635 ,
Code
350627:| 615 E = -447.349 dE =  4.819839e-04 dH =  2.388363e-04
350846:| 616 E =  -447.35 dE =  9.950206e-04 dH =  8.781832e-04
351065:| 617 E =  -447.35 dE =  1.495225e-04 dH =  1.050059e-03
351284:| 618 E = -447.349 dE =  7.514605e-04 dH =  2.417407e-04
351503:| 619 E = -447.349 dE =  8.285889e-05 dH =  1.792596e-04
351722:| 620 E = -447.348 dE =  6.273245e-04 dH =  1.333994e-04
351941:| 621 E = -447.348 dE =  4.864245e-04 dH =  3.458751e-04
352160:| 622 E = -447.348 dE =  1.074768e-04 dH =  2.376046e-04
352379:| 623 E = -447.349 dE =  6.705824e-04 dH =  3.217824e-04
352598:| 624 E = -447.348 dE =  6.934614e-04 dH =  3.254210e-04
352817:| 625 E = -447.348 dE =  3.242197e-04 dH =  2.692547e-04
353036:| 626 E = -447.348 dE =  1.095985e-04 dH =  1.103893e-04
353255:| 627 E = -447.349 dE =  7.666417e-04 dH =  1.624413e-04
353474:| 628 E = -447.349 dE =  1.769304e-05 dH =  4.870540e-04
353693:| 629 E = -447.348 dE =  8.042218e-04 dH =  1.483390e-04
353912:| 630 E = -447.348 dE =  1.963235e-06 dH =  2.435271e-04
354131:| 631 E = -447.349 dE =  6.199732e-04 dH =  5.196899e-04
354350:| 632 E = -447.348 dE =  5.375404e-04 dH =  1.000946e-04
354569:| 633 E = -447.348 dE =  1.350441e-05 dH =  1.004250e-04
354788:| 634 E = -447.348 dE =  1.106934e-04 dH =  1.264113e-04
355007:| 635 E = -447.348 dE =  3.390452e-05 dH =  9.519258e-05
355462:|   0 E = -428.204 dE =  1.917845e+01 dH =  1.470380e-01
355681:|   1 E = -439.981 dE =  1.177661e+01 dH =  3.916571e+00
355900:|   2 E = -445.977 dE =  5.996319e+00 dH =  7.775032e-01
356119:|   3 E = -446.527 dE =  5.499668e-01 dH =  2.842024e-01
356338:|   4 E = -446.857 dE =  3.301646e-01 dH =  8.742580e-02
356557:|   5 E = -446.732 dE =  1.250417e-01 dH =  1.973932e-01
356776:|   6 E = -446.928 dE =  1.960541e-01 dH =  8.639483e-02
356995:|   7 E = -446.951 dE =  2.286883e-02 dH =  8.455163e-02
357214:|   8 E = -447.205 dE =  2.537133e-01 dH =  9.177060e-02
357433:|   9 E = -447.073 dE =  1.319129e-01 dH =  7.540765e-02
357652:|  10 E = -447.258 dE =  1.854489e-01 dH =  5.404163e-02
357871:|  11 E = -447.261 dE =  3.214866e-03 dH =  8.341868e-02
358090:|  12 E = -447.239 dE =  2.249815e-02 dH =  6.084702e-02
358309:|  13 E = -447.096 dE =  1.428855e-01 dH =  5.987770e-02
358528:|  14 E = -447.068 dE =  2.819535e-02 dH =  4.608637e-02
358747:|  15 E = -447.118 dE =  5.013750e-02 dH =  8.704623e-02
358966:|  16 E = -447.188 dE =  6.975315e-02 dH =  6.939250e-02
359185:|  17 E = -447.285 dE =  9.755813e-02 dH =  1.863129e-01

but when i  set  same max step in another restarting py ,
Code
#----------------------------------------
# Iteration Control Settings
#----------------------------------------
left_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=1000,
    )

right_electrode_iteration_control_parameters = IterationControlParameters(
    max_steps=1000,
    )

device_iteration_control_parameters = IterationControlParameters(
    damping_factor=0.36,
    max_steps=2000,
    number_of_history_steps=8,
    )

#----------------------------------------
# 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]]
    )

#----------------------------------------
# Contour Integral Settings
#----------------------------------------
contour_parameters = DoubleContourIntegralParameters(
    real_axis_infinitesimal=1e-06*Rydberg,
    real_axis_point_density=0.02*eV,
    integral_lower_bound=50.0*eV,
    )

#----------------------------------------
# Electrode Calculators
#----------------------------------------
left_electrode_calculator = LCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=left_electrode_iteration_control_parameters,
    poisson_solver=left_electrode_poisson_solver,
    )

right_electrode_calculator = LCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=right_electrode_iteration_control_parameters,
    poisson_solver=right_electrode_poisson_solver,
    )

#----------------------------------------
# Device Calculator
#----------------------------------------
calculator = DeviceLCAOCalculator(
    basis_set=basis_set,
    exchange_correlation=exchange_correlation,
    iteration_control_parameters=device_iteration_control_parameters,
    contour_parameters=contour_parameters,
    electrode_calculators=
        [left_electrode_calculator, right_electrode_calculator],
    )

device_configuration.setCalculator(calculator)

# -------------------------------------------------------------
# Initial State
# -------------------------------------------------------------
initial_spin = InitialSpin(scaled_spins=[0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 0.0])
device_configuration.setCalculator(
    calculator,
    initial_spin=initial_spin,
)
device_configuration = nlread("ivcurve_selfconsistent_configurations_bias_-0.1.nc")[0]
device_configuration.update(force_restart=True)
nlsave('CONFIG.nc', device_configuration)
nlprint(device_configuration)

# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
calculator=device_configuration.calculator()

biases = [-0.200000, -0.300000, -0.400000, -0.500000,
          -0.600000, -0.700000, -0.800000, -0.900000, -1.000000]*Volt
for bias in biases:
    calculator=calculator(
            electrode_voltages=(bias/2, -bias/2))

    device_configuration.setCalculator(
          calculator(),
          initial_state=device_configuration)
    device_configuration.update()
    nlsave("ivcurve_selfconsistent_configurations_bias_%g.nc" % bias.inUnitsOf(Volt), device_configuration)


it stopped in the step=499 (i should mentioned that in the previous V= -0.1,i used max steps as 500) ,so i wonder if it is because the restarting for -0.1 make the new max step =2000 invalid ,can anyone explain about it ?

5
hello,quantumwise staff :
1.i also met the restarting problems ,here is my confusion:
   there are so many verisions of restart a bias dependent calculation ,but i can't get the uniform answer about it ,there is basically two answers  in the forum :
   first solution ,
Code
# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
calculator=device_configuration.calculator()
device_configuration = nlread("ivcurve_selfconsistent_configurations_bias_0.nc",)[0]

     second solution,
Code
device_configuration.setCalculator(calculator)
nlprint(device_configuration)
device_configuration = nlread("ivcurve_selfconsistent_configurations_bias_0.nc")[0]
device_configuration.update(force_restart=True)
nlsave('CONFIG.nc', device_configuration)
     
      I don't know  the accuracy and differences between these two solutions  and in the
Code
 nlread("ivcurve_selfconsistent_configurations_bias_0.nc")[0]
,what is the exact meaning of
  • and [-1],or when should i use
  • and [-1],what is the exact meaning of 
    Code
    force_restart=True
    .
    2.i am also very confused about the restarting procedure ,can you explain about it ?In another posthttp://quantumwise.com/forum/index.php?topic=1374.msg6752#msg6752 ,it tells me that the restarting procedure includes these steps :
    1.) read Electrode
    2.) read checkpoint-file  (== equiv. bulk)
    3.) create Device from equiv. Bulk and electrodes
    4.) attach a new device calculator
    5.) update
     Hope you can give us a detailed description of the equiv bulk and the  restarting procedure .

6
Thank you for your precise correction . :).

7
Hello ,every one .For a  spin dependent two-probe  deviceI, i am running  the I-V calculation and  confused about how  to calculate the bandstructure under a certain bias for the electrode after the I-V calculation  .This is my thought: i need to analyse the iv-scf converged device configuration ,but how should i apply it to my left/right electrode ,in another words, how should i write in my code to read the bias left/right electrode configuration and its spin state for my iv-scf converged device configuration  . I can't find any information in the forum and toturial about the detailed items.
Code
# -------------------------------------------------------------
# Bulk Configuration
# -------------------------------------------------------------

# Set up lattice
vector_a = [37.2364702358, 0.0, 0.0]*Angstrom
vector_b = [0.0, 23.17211, 0.0]*Angstrom
vector_c = [0.0, 0.0, 9.43074]*Angstrom
lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
elements = [Sulfur, Sulfur, Sulfur, Sulfur, Molybdenum, Molybdenum, Molybdenum,
            Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Molybdenum,
            Molybdenum, Molybdenum, Molybdenum, Sulfur, Sulfur, Sulfur, Sulfur,
            Sulfur, Sulfur, Sulfur, Molybdenum, Molybdenum, Molybdenum, Sulfur,
            Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Molybdenum,
            Molybdenum, Molybdenum, Molybdenum, Sulfur, Sulfur, Sulfur, Sulfur,
            Sulfur, Sulfur, Sulfur, Molybdenum, Molybdenum, Molybdenum, Sulfur,
            Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Sulfur, Molybdenum,
            Molybdenum, Molybdenum, Molybdenum, Sulfur, Sulfur, Sulfur]

# Define coordinates
fractional_coordinates = [[ 0.292994142293,  0.43155327676 ,  0.083333333329],
                          [ 0.439217461613,  0.43155327676 ,  0.083333333329],
                          [ 0.585440780933,  0.43155327676 ,  0.083333333329],
                          [ 0.731664100254,  0.43155327676 ,  0.083333333329],
                          [ 0.34199604229 ,  0.499999999998,  0.083333333329],
                          [ 0.48821936161 ,  0.499999999998,  0.083333333329],
                          [ 0.634442680931,  0.499999999998,  0.083333333329],
                          [ 0.292994142293,  0.568446723236,  0.083333333329],
                          [ 0.439217461613,  0.568446723236,  0.083333333329],
                          [ 0.585440780933,  0.568446723236,  0.083333333329],
                          [ 0.731664100254,  0.568446723236,  0.083333333329],
                          [ 0.366105801953,  0.43155327676 ,  0.249999999997],
                          [ 0.512329121273,  0.43155327676 ,  0.249999999997],
                          [ 0.658552440594,  0.43155327676 ,  0.249999999997],
                          [ 0.26888438263 ,  0.499999999998,  0.249999999997],
                          [ 0.41510770195 ,  0.499999999998,  0.249999999997],
                          [ 0.561331021271,  0.499999999998,  0.249999999997],
                          [ 0.707554340591,  0.499999999998,  0.249999999997],
                          [ 0.366105801953,  0.568446723236,  0.249999999997],
                          [ 0.512329121273,  0.568446723236,  0.249999999997],
                          [ 0.658552440594,  0.568446723236,  0.249999999997],
                          [ 0.292994142293,  0.43155327676 ,  0.416666666664],
                          [ 0.439217461613,  0.43155327676 ,  0.416666666664],
                          [ 0.585440780933,  0.43155327676 ,  0.416666666664],
                          [ 0.731664100254,  0.43155327676 ,  0.416666666664],
                          [ 0.34199604229 ,  0.499999999998,  0.416666666664],
                          [ 0.48821936161 ,  0.499999999998,  0.416666666664],
                          [ 0.634442680931,  0.499999999998,  0.416666666664],
                          [ 0.292994142293,  0.568446723236,  0.416666666664],
                          [ 0.439217461613,  0.568446723236,  0.416666666664],
                          [ 0.585440780933,  0.568446723236,  0.416666666664],
                          [ 0.731664100254,  0.568446723236,  0.416666666664],
                          [ 0.366105801953,  0.43155327676 ,  0.583333333331],
                          [ 0.512329121273,  0.43155327676 ,  0.583333333331],
                          [ 0.658552440594,  0.43155327676 ,  0.583333333331],
                          [ 0.26888438263 ,  0.499999999998,  0.583333333331],
                          [ 0.41510770195 ,  0.499999999998,  0.583333333331],
                          [ 0.561331021271,  0.499999999998,  0.583333333331],
                          [ 0.707554340591,  0.499999999998,  0.583333333331],
                          [ 0.366105801953,  0.568446723236,  0.583333333331],
                          [ 0.512329121273,  0.568446723236,  0.583333333331],
                          [ 0.658552440594,  0.568446723236,  0.583333333331],
                          [ 0.292994142293,  0.43155327676 ,  0.74999999999 ],
                          [ 0.439217461613,  0.43155327676 ,  0.74999999999 ],
                          [ 0.585440780933,  0.43155327676 ,  0.74999999999 ],
                          [ 0.731664100254,  0.43155327676 ,  0.74999999999 ],
                          [ 0.34199604229 ,  0.499999999998,  0.74999999999 ],
                          [ 0.48821936161 ,  0.499999999998,  0.74999999999 ],
                          [ 0.634442680931,  0.499999999998,  0.74999999999 ],
                          [ 0.292994142293,  0.568446723236,  0.74999999999 ],
                          [ 0.439217461613,  0.568446723236,  0.74999999999 ],
                          [ 0.585440780933,  0.568446723236,  0.74999999999 ],
                          [ 0.731664100254,  0.568446723236,  0.74999999999 ],
                          [ 0.366105801953,  0.43155327676 ,  0.916666666657],
                          [ 0.512329121273,  0.43155327676 ,  0.916666666657],
                          [ 0.658552440594,  0.43155327676 ,  0.916666666657],
                          [ 0.26888438263 ,  0.499999999998,  0.916666666657],
                          [ 0.41510770195 ,  0.499999999998,  0.916666666657],
                          [ 0.561331021271,  0.499999999998,  0.916666666657],
                          [ 0.707554340591,  0.499999999998,  0.916666666657],
                          [ 0.366105801953,  0.568446723236,  0.916666666657],
                          [ 0.512329121273,  0.568446723236,  0.916666666657],
                          [ 0.658552440594,  0.568446723236,  0.916666666657]]

# Set up configuration
bulk_configuration = BulkConfiguration(
    bravais_lattice=lattice,
    elements=elements,
    fractional_coordinates=fractional_coordinates
    )

# Add tags
bulk_configuration.addTags('Left')

# -------------------------------------------------------------
# Analysis from File
# -------------------------------------------------------------
bulk_configuration = nlread('ivcurve_selfconsistent_configurations_bias_0.4.nc', object_id='gID000')[0]

# -------------------------------------------------------------
# Bandstructure
# -------------------------------------------------------------
bandstructure = Bandstructure(
    configuration=bulk_configuration,
    route=['G', 'Z'],
    points_per_segment=20,
    bands_above_fermi_level=All
    )
nlsave('Device Device-1-7 (1) (left electrode).nc', bandstructure)
.
This is my code  and i am not sure if it is right or wrong .

8
Thanks for your kind suggestion,The updated example of  Spin-dependent Bloch states in graphene nanoribbons is in the http://docs.quantumwise.com/tutorials/spin_bloch_gnr.html?highlight=spin%20density .It quickly solved my confusion .As you said ,there is no wrong or right color in my spin density difference plot,all i need to do is to modify the isovalue  and choose  the appropriate color map to make it look more nice.

9
Thank you very much to  professor Umberto ,i realised the new search docs websitehttp://docs.quantumwise.com/index.html is very useful  for new learners like me.

10
Hello,i recently learned the spin density from the http://www.quantumwise.com/documents/tutorials/latest/GrapheneBloch/index.html/electrondensity.spin.html,The block state and the band structure is normal ,but when i calculated the spin density difference and visualize it in the view  subframe,it turned out that the color and the pattern is not consistent with the the Mulliken populations that the numbers 0 and 1) have a surplus population of 0.25 of either spin-up or spin-down.I read some literatures that the spin density is usually red and blue ,i change the color map ,it still exhibited wrong  color.can anyone help me fix it ?

11
Hello, i tried to optimize the lattice constant of the MoS2 recently ,i read the tutorial http://quantumwise.com/forum/index.php?topic=29.0.I used the easy  GaN.py example  and modified it as
Code
from stress_optimizers import *
import ATK; ATK.setVerbosityLevel(1)
from ATK.KohnSham import *
# Select Bravais lattice and define lattice constants
bravais_lattice = Hexagonal(
    a=3.160400 * Angstrom,
    c=12.29500 * Angstrom
    )

# Define bulk elements and unit cell coordinates
elements = [Molybdenum, Molybdenum, Sulfur, Sulfur, Sulfur, Sulfur]
coordinates = [[ 1.5802      ,  0.9123289,  3.073750   ],
               [ 1.5802      , -0.9123289,  9.221250   ],
               [ 1.5802      ,  0.9123289,  7.635195   ],
               [ 1.5802      , -0.9123289,  1.487695   ],
               [ 1.5802      ,  0.9123289,  10.80730   ],
               [ 1.5802      , -0.9123289,  4.659805   ]]*Angstrom 
# Set up bulk configuration
bulk_configuration = BulkConfiguration(
    bravais_lattice,
    elements,
    cartesian_coordinates=coordinates
    )

method = KohnShamMethod(brillouin_zone_integration_parameters = brillouinZoneIntegrationParameters((5,5,5)),
                        basis_set_parameters = basisSetParameters())
opt_conf = calculateOptimizedBulkConfiguration(bulk_configuration, method, runtimeParameters(1))
.
 runed it on my cluster  and the version is ATK2015.It quickly returned the error message:
Code
Traceback (most recent call last):
  File "MoS2.py", line 1, in <module>
Traceback (most recent call last):
  File "MoS2.py", line 1, in <module>
Traceback (most recent call last):
  File "MoS2.py", line 1, in <module>
Traceback (most recent call last):
  File "MoS2.py", line 1, in <module>
    from stress_optimizers import *
    from stress_optimizers import *
    from stress_optimizers import *
ImportError: No module named stress_optimizersImportError: No module named stress_optimizers
ImportError: No module named stress_optimizers
.
I am not aware about the program codes in ATK and can't fix this problem.

Thanks.

12
Thank you  for pointing out the reasons of the two errors .I have confirmed that the deadline of the  trial key is 21th of  January,i will  ask the ATK agent in china for offical key since we have bought the ATK for several months.

13
Recently i ran two  device with wo - dimensional materials ,it has  340 atoms .They both return the error message.
Code
Server could not re-checkout feature because:
Software expired
.Some detailed maeesage are :
Code
|  332   S   [  13.649 ,  13.172 ,  50.033 ]    3.09984   3.07110   0.17094    |
|  333   S   [  19.123 ,  13.172 ,  50.033 ]    3.08572   3.08115   0.16687    |
|  334   S   [  24.597 ,  13.172 ,  50.033 ]    3.11573   3.03993   0.15566    |
|  335   S   [  30.071 ,  13.172 ,  50.033 ]    3.45875   2.63973   0.09848    |
+------------------------------------------------------------------------------+
|  99 E = -711.003 dE =  1.849073e-04 dH =  2.930977e-04                       |
+------------------------------------------------------------------------------+
|                                                                              |
| Fermi Level  = -4.229089 eV                                                  |
+------------------------------------------------------------------------------+
################################################################################
#                                                                              #
# Warning: The calculation did not converge to the requested tolerance!        #
#                                                                              #
################################################################################
+------------------------------------------------------------------------------+
|                                                                              |
| DFT Calculation  [Finished Thu Jan 21 23:48:51 2016]                         |
|                                                                              |
+------------------------------------------------------------------------------+
Code
+------------------------------------------------------------------------------+
|   1 E = -710.931 dE =  1.668908e-01 dH =  8.603409e-02                       |
+------------------------------------------------------------------------------+

                            |--------------------------------------------------|
Calculating Eigenvalues    : Connection to server [ localhost : 6200 ] lost - trying to reconnect.
Server could not re-checkout feature because:
Software expired

===================================================================================
=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
=   EXIT CODE: 1
=   CLEANING UP REMAINING PROCESSES
=   YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================
.
I have another problems that i set
Code
# -------------------------------------------------------------
# Optimize Geometry
# -------------------------------------------------------------
indices_0 = [192, 193, 194, 195, 196, 197, 198, 199, 200, 201,
             202, 203, 204, 205, 206, 207, 208, 209, 210, 211,
             212, 213, 214, 215, 216, 217, 218, 219, 220, 221,
             222, 223, 224, 225, 226, 227, 228, 229, 230, 231,
             232, 233, 234, 235, 236, 237, 238, 239, 240, 241,
             242, 243, 244, 245, 246, 247, 248, 249, 250, 251,
             252, 253, 254, 255, 256, 257, 258, 259, 260, 261,
             262, 263, 264, 265, 266, 267, 268, 269, 270, 271,
             272, 273, 274, 275, 276, 277, 278, 279, 280, 281,
             282, 283, 284, 285, 286, 287, 288, 289, 290, 291,
             292, 293, 294, 295, 296, 297, 298, 299, 300, 301,
             302, 303, 304, 305, 306, 307, 308, 309, 310, 311,
             312, 313, 314, 315, 316, 317, 318, 319, 320, 321,
             322, 323, 324, 325, 326, 327, 328, 329, 330, 331,
             332, 333, 334, 335]
indices_1 = [  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,
              10,  11,  12,  13,  14,  15,  16,  17,  18,  19,
              20,  21,  22,  23,  24,  25,  26,  27,  28,  29,
              30,  31,  32,  33,  34,  35,  36,  37,  38,  39,
              40,  41,  42,  43,  44,  45,  46,  47,  48,  49,
              50,  51,  52,  53,  54,  55,  56,  57,  58,  59,
              60,  61,  62,  63,  64,  65,  66,  67,  68,  69,
              70,  71,  72,  73,  74,  75,  76,  77,  78,  79,
              80,  81,  82,  83,  84,  85,  86,  87,  88,  89,
              90,  91,  92,  93,  94,  95,  96,  97,  98,  99,
             100, 101, 102, 103, 104, 105, 106, 107, 108, 109,
             110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
             120, 121, 122, 123, 124, 125, 126, 127, 128, 129,
             130, 131, 132, 133, 134, 135, 136, 137, 138, 139,
             140, 141, 142, 143]
constraints = [RigidBody(indices_0), RigidBody(indices_1)]

bulk_configuration = OptimizeGeometry(
        bulk_configuration,
        max_forces=0.05*eV/Ang,
        max_steps=500,
        max_step_length=0.2*Ang,
        constraints=constraints,
        trajectory_filename='trajectory.nc',
        disable_stress=True,
        optimizer_method=LBFGS(),
        )
nlsave('Device-heterojunctions2.nc', bulk_configuration)
nlprint(bulk_configuration)

my max_steps=500,why it stops when the step=99 and
Code
 the dE =  1.849073e-04 dH =  2.930977e-04    
.

14
Thank you every much.To see the unit cell both ,one need to  drag both icon to the view in the left panel ,not in the right view botton.If you use the right view botton ,no matter how you try to pick the two icon  and insert the botton ,it can't work. It's a slight bug but not affecting the usage ,Hope ATK can fix the problem in the right view botton .Two pictures using left view icon and right view botton are in the attachments.

15
The nc file is too large ,so i didn.t post it .The point i want to explain is that i save all the output.nc to one file as it can be seen in the py file

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