Recent Posts

81

General Questions and Answers / Extract 3D/2D potential profile as a text file

« Last post by maheswari on March 11, 2024, 11:34 »

Hi, I am interested in getting the raw data (in txt or excel) of the 3D or 2D potential profile of across the device. I could see the 2D image using Viewer, but I don't see an option to extract the raw data. Alternatively, when I tried the "Text Representation" tool, it was hard to read the file since there was no label. It seems to have 6 columns. Is this (x,y,z, potential)? If all the data is just potential, where do I get the (x,y,z) information? Where do I find the information related to sampling? I have attached the snapshot of the output file for your reference.

Thanks!

82

General Questions and Answers / Re: Zero bias transmission

« Last post by AsifShah on March 9, 2024, 10:55 »

Dear Ander Bloms,

Thanks for your response. I still have a doubt, when you say QATK includes the effects of all atoms, "Does that mean it takes account of an electron scattering from energy E1 to E2? In other words, if an electron is traveling with energy E1 from the electrode and encounters a scatterer in the central region taking it to energy E2, will such an event be included in the transmission calculated from QATK?"

83

General Questions and Answers / Re: What is the current option for the previous "Analysis from File"?

« Last post by Anders Blom on March 9, 2024, 00:54 »

Good question, happy that we get a chance to answer it here for the benefit of all users.

• Start we a fresh empty workflow in the Workflow Builder
• Insert a "Load from file" block from the Algorithms group and double-click the inserted block to open it
• Click the button "Load from file" and select the file and object in the file that you want to read in
• Close the "Load from file" widget
• Now you can add any analysis you want to the script. Usually it's automatically connected to the loaded object, if not (some analysis takes multiple input configurations) you can connect them manually by clicking the little colorful icons on the right (next to the red warning badge that appears in these situations).

I didn't make screenshots as I hope it's clear already but let me know if you need more guidance.

84

General Questions and Answers / Re: Zero bias transmission

« Last post by Anders Blom on March 9, 2024, 00:37 »

The term "ballistic" is somewhat ambiguous. In our NEGF mode it's taken to mean the opposite of diffusive (as in "ballistic transport", below the mean free path, i.e. no energy relaxation from phonon scattering), since we include scattering of interfaces, defects, surface roughness, etc as created by any atom not in a perfectly periodic arrangement. In some other models i's defined it as "no scattering at all", which would only be possible in a perfect crystal, and thus is rather uninteresting in an atomistic picture, but makes sense in higher-level models when you only use the mobility or set transmission to 1 to model a ballistic conductor.

No matter the bias, the transmission spectrum is computed including the effects of all atoms present in the system.

85

General Questions and Answers / Re: NLIOError in calculating Transmission Spectra

« Last post by Anders Blom on March 9, 2024, 00:22 »

This is confusing, as this error has nothing to do running a script (no matter what task, like TransmissionSpectrum), but rather is related to the GUI itself and how it stores the status of running jobs. Do you see the error in the script log file or does the GUI crash?

86

General Questions and Answers / High Voltage Discrepancy [ electric field calculations ]

« Last post by maj7293 on March 8, 2024, 12:28 »

Hello,

I'm calculating the band structure for a bilayer of MnBi2Te4 and encountering a significant difference in voltage magnitudes compared to literature values.

In Quantum ATK, my understanding is that we have two metallic regions with varying voltages, and the electric field (E) is calculated based on the distance (d) between them using E = v/d. However, applying this voltage doesn't yield a band structure comparable to literature.

For instance, literature reports E = 10 mV/Å. Given a distance between the electrodes of c= 50 Å , I would expect to apply a voltage of 0.05 V. With this value, the calculated band structure doesn't match the literature. Interestingly, increasing the voltage to 10 V brings the results into agreement. I'm unsure why this behavior occurs.

Any help in understanding this would be greatly appreciated.

Thanks!

87

General Questions and Answers / Re: NLIOError in calculating Transmission Spectra

« Last post by wangmz on March 8, 2024, 02:29 »

Yesterday when I start this task the first time, there was no Error. But after this error appears the first time, it would  re-appear immediately when it start to calculate TransmissionSpectrum.

88

General Questions and Answers / Re: NLIOError in calculating Transmission Spectra

« Last post by wangmz on March 8, 2024, 02:26 »

The script was generated by a workflow:
1. Load Device Configuration
2. Set Initial Spin
3. Set DeviceLCAOCalculator
4. Transmission Spectrum

And the Transmission Spectrum part of the script was like this:

Code

# %% TransmissionSpectrum

self_energy_calculator = RecursionSelfEnergy(
    storage_strategy=StoreOnDisk()
)

transmission_spectrum = TransmissionSpectrum(
    configuration=cr_al_l1,
    energies=numpy.linspace(-0.5, 0.5, 11)*eV,
    kpoints=AdaptiveGrid(),
    self_energy_calculator=self_energy_calculator
)
nlsave('results.hdf5', transmission_spectrum)

89

General Questions and Answers / Re: NLIOError in calculating Transmission Spectra

« Last post by wangmz on March 8, 2024, 02:19 »

And I run the task again, comes:

Traceback (most recent call last):
  File "zipdir\NL\GUI\Tools\Jobs\TaskExecutor.py", line 390, in _onWorkerChanged
  File "zipdir\NL\GUI\Store\Store.py", line 306, in update
  File "build\atkpython\Lib\contextlib.py", line 144, in __exit__
  File "zipdir\NL\GUI\Store\Store.py", line 675, in batch
  File "zipdir\NL\GUI\Store\Store.py", line 734, in _closeTransaction
  File "zipdir\NL\GUI\Store\Signal.py", line 143, in emit
  File "zipdir\NL\GUI\Store\StoreDatabase.py", line 203, in _onTransaction
  File "build\atkpython\Lib\contextlib.py", line 155, in __exit__
  File "zipdir\NL\GUI\Store\StoreDatabase.py", line 194, in transaction
NL.ComputerScienceUtilities.Exceptions.NLIOError: Failed to commit transaction

Everything looks fine until Transmission Spectra

90

General Questions and Answers / NLIOError in calculating Transmission Spectra

« Last post by wangmz on March 8, 2024, 02:11 »

Does someone know the reason of this error? Now the error occurs whenever I start to calculate Transmission Spectra.

The version of the ATK I use is V-2023.12.

Traceback (most recent call last):
  File "zipdir\NL\GUI\Tools\Data\DataCatalogImportThreader.py", line 65, in start
  File "zipdir\NL\GUI\Tools\Data\DataCatalogImportThreader.py", line 189, in start
  File "build\atkpython\Lib\contextlib.py", line 155, in __exit__
  File "zipdir\NL\GUI\Tools\Data\DataCatalog.py", line 259, in transaction
NL.ComputerScienceUtilities.Exceptions.NLIOError: Failed to commit transaction