Recent Posts

1

Questions and Answers / Optimization structure

« Last post by Roc2019 on Today at 02:08 »

Dear Sir,
How to fix the Space Group and the Bravais Lattice type as optimize the geometry of one 2D material?  i.e. let the both parameters remain unchanged.

Thanks.

2

Questions and Answers / Re: Phonon bandstructure

« Last post by Petr Khomyakov on Yesterday at 14:02 »

Could you post your script and log file to see what could be done about it?

3

Questions and Answers / Re: how to reset some parameters after ivcurve calculation not convergence

« Last post by Petr Khomyakov on Yesterday at 14:00 »

The damping factor is set in the iteration control parameters in the Calculator, see https://docs.quantumatk.com/manual/Types/IterationControlParameters/IterationControlParameters.html.

4

Questions and Answers / Re: spin transfer torque - reg.

« Last post by Petr Khomyakov on Yesterday at 13:55 »

I was unable to reproduce this warning with your script (para.py). I assume that you have used QATK-2019.03-SP1 for doing this calculation, as evident from your log file. I notice that this is just a warning, not error message, and your calculation seems to run, even so the message was given.

5

Questions and Answers / Re: the Curie temperature

« Last post by Petr Khomyakov on Yesterday at 08:57 »

One way of doing it would be to build a spin Hamiltonian, see https://repositories.lib.utexas.edu/handle/2152/ETD-UT-2010-08-2012 for details. In QuantumATK, that could be done through total energy calculations for a set of magnetic configurations, or using Heisenberg exchange module to compute J-parameters of Heisenberg exchange coupling, see https://docs.quantumatk.com/manual/Types/HeisenbergExchange/HeisenbergExchange.html.

6

Questions and Answers / the Curie temperature

« Last post by Roc2019 on September 15, 2019, 04:23 »

Dear Sir,
Can the ATK (2019.3) calculate the the Curie temperature of a 2D material?   Thanks.

7

Questions and Answers / Re: spin transfer torque - reg.

« Last post by rebeda on September 13, 2019, 08:30 »

Dear Sir,

I would like to know the status of my issue......

Regards,

Rebeda

8

Questions and Answers / Re: Dipole Transition probability

« Last post by Petr Khomyakov on September 12, 2019, 15:51 »

At the moment, there is no implemented feature in QuantumATK to output dipole matrix elements, even so it is indeed computed in Optical Spectrum analysis object.

9

Questions and Answers / how to reset some parameters after ivcurve calculation not convergence

« Last post by njuxyh on September 11, 2019, 15:02 »

Hi, I know if at some bias point for example at 0.4v,  the calculation did not convergence, I can try some setting such as   damping_factor.
i don how to write the script to reset these parameters.where to add the resetting parameter?
i read a convergence zero bias hdf5 file as a start point

path = './test-t-relax.hdf5'
configuration = nlread(path, object_id='DeviceConfiguration_0')[0]

# -------------------------------------------------------------
# IV Curve
# -------------------------------------------------------------
biases = [0.000000, 0.100000, 0.200000, 0.300000, 0.400000, 0.500000,
          0.600000, 0.700000, 0.800000, 0.900000, 1.000000, 1.100000,
          1.200000]*Volt

kpoint_grid = MonkhorstPackGrid()

iv_curve = IVCurve(
    configuration=configuration,
    biases=biases,
    energies=numpy.linspace(-3,3,301)*eV,
    kpoints=kpoint_grid,
    self_energy_calculator=RecursionSelfEnergy(),
    energy_zero_parameter=AverageFermiLevel,
    infinitesimal=1e-06*eV,
    selfconsistent_configurations_filename_prefix="ivcurve_selfconsistent_configuration_",
    log_filename_prefix="ivcurve_"
    )
nlsave('iv-t.hdf5', iv_curve)

10

Questions and Answers / Re: work function of bulk material

« Last post by Anders Blom on September 10, 2019, 20:58 »

Thanks for the quick response.
Then, for the bulk work function calculation, do I need to set up a thick slab to mimic the bulk and then do the work function calculation?

The slab approach is one option, the other is using the unique surface Green's function method in QuantumATK. See
https://docs.quantumatk.com/tutorials/work_function_ag_100/work_function_ag_100.html
https://docs.quantumatk.com/tutorials/work_function_tuning/work_function_tuning.html
https://docs.quantumatk.com/tutorials/gf_surface/gf_surface.html