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Topics - Parveen

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1
What is the charge transfer mechanism that is followed in ghost atoms in M-I-S-M device structure? That is Metal- Insulator- Space(ghost atoms)- Metal devices. Is it any kind of tunneling like direct/FN or charge hopping?

2
Hi,
      I was looking for usage example for STM kind of calculation in latest ATK v2018.06. But unable to find any. can anyone please share the example script for such calculations. Moreover I was expecting a new bulk to device tool in builder in v2018.06 or else STM analysis in Analysis section. But unable to found any. If anyone able to utilize the keyword meant for STM study then kindly share.

3
I was looking for the formulation for transmission coefficient used in VNL ATK. Is it Breit-Wigner formula? can you provide related reference?

4
Hi

I'm re-posting this issue that i encountered few months ago. see the conversation at (https://quantumwise.com/forum/index.php?topic=4894.msg21177#msg21177) where I raised that the different in current value by IV plot and transmission analyser. I re-run the entire process considering same parameters as in IV curve analysis and FBTS analysis. But problem still persist. I request you to please send your e mail address so that i can send you desired scripts.

5
Hi

I would like to know that is it possible to perform scanning tunnelling microscopy (STM) kind of calculations with the help of VNL-ATK 2014.3 through python script? I was checking into Manual section and I found keyword for STM calculations http://docs.quantumwise.com/manuals/Types/STM/STM.html . I just want to know if ATK 2014.3 is able to read this keyword?

Thanks

6
Hi

I was trying to analyse the transmission eigen states post-IV. In transmission analyzer I noticed that the value of current was different from that obtained from IV plot at same bias voltage. can you please explain why this is so?

Thank you

7
General Questions and Answers / Eigen State Calculation error
« on: August 6, 2016, 11:42 »
Hi,

I was trying to determine the Eigen States for my device for quantum numbers somewhat far from those near to HOMO and LUMO levels but end up with following error. I can't figure out why it is showing incompatibility error though i made the script from current version only. Please look at the error message.

Traceback (most recent call last):
File "./zipdir/NL/GUI/MainWindow/LabFloor/LabFloorModel.py", line 201, in load
File "/opt/QuantumWise/atk-13.8.1/vnl/lib/python2.7/site-packages/AddOns/ATKNCImporter/ATKNCImporter.py", line 138, in load
return nlread(filename, object_id=object_id, read_state=False)[0]
File "./zipdir/NL/IO/NLSaveUtilities.py", line 327, in nlread
NLIOError: The NetCDF file, 'Au_ddq_OG_test5_Au_ES1.nc', cannot be read by the current version of ATK (ATK 13.8.1), since the file is generated by an incompatible (probably later) version (ATK 2014.3).


Thank you

8
Hi All,

From where I can find the list of all python script keywords used in VNL-ATK.


Thank you

9
Hi All,

I was trying to plot LDDOS plot for a device structure and end up with a plot looks like multiple LDDOS plots are merged onto same plot. I can't figure out if it a real plot or i went wrong somewhere while plotting it. Also tell me what is the significance of plotting it. Is it for the counter-check of the results obtained by Transmission spectra? what does Transmission coefficient T(E)>1 signifies in context of LDDOS plot.

Thank you

10
General Questions and Answers / Molecular Dynamics Error
« on: January 11, 2016, 09:08 »
Hi All,

I was trying to make minimum energy state Metal-Insulator-Metal (MIM) structure with insulator being an organic molecule. But i got this error after execution completed.

  File "/tmp/5701470339676073.py", line 27, in <module>
    method=method
  File "./zipdir/NL/Dynamics/MolecularDynamics/MolecularDynamics.py", line 215, in MolecularDynamics
  File "./build/atkpython/lib/python2.7/site-packages/ase/md/nptberendsen.py", line 110, in step
  File "./build/atkpython/lib/python2.7/site-packages/ase/md/nptberendsen.py", line 100, in scale_positions_and_cell
  File "./zipdir/NL/Dynamics/ASEAtomsInterface.py", line 352, in set_cell
AttributeError: 'DeviceConfiguration' object has no attribute '_setBravaisLattice'


I did following modifications

1) convert bulk structure to device structure
2) Apply Fit Cell in Bulk Tools
3) Sent it to script generator
4)  Add New calculator
5) Add MolecularDynamics from optimization
6)  In New calculator i take ATK-DFT calculator
7) In Molecular Dynamics I take NPT Berendsen Type
8 ) in constraints i select left and right electrode metal atoms
9) keep all other parameters as default.

I want to ask you why i am facing this problem. Is that because of asymmetry of device or anything else. Please help

11
i was trying to run this script already given in molecular device reference at http://quantumwise.com/documents/tutorials/latest/MolecularDevice/index.html/chap.iv.html#sect1.iv.lddos

the script is under headline of THE LDDOS AT 1.6V

configuration = nlread('au_dtb_au.nc', DeviceConfiguration)[8]

# make list of energies to be used for ldos
energies = numpy.linspace(-3,3,31)

# calculate ldos for each energy in the list
for e in energies:
    local_device_density_of_states = LocalDeviceDensityOfStates(
        configuration=configuration,
        energy=e*eV,
        kpoints=MonkhorstPackGrid(3,3),
        contributions=All,
        energy_zero_parameter=AverageFermiLevel,
        infinitesimal=1e-06*eV,
        self_energy_calculator=RecursionSelfEnergy(),
        spin=Spin.Sum,
        )
    nlsave(r'lddos16.nc', local_device_density_of_states)

when i run this script with the help of job manager, it return me a log file with error

Traceback (most recent call last):
  File "/tmp/2438853653008193.py", line 20, in <module>
    spin=Spin.Sum,
TypeError: __init__() got an unexpected keyword argument 'spin'


please suggest me what shall i modify.
Thank you

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