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General Questions and Answers / Re: HartreeDifferencePotential caculation 2
« on: September 24, 2025, 00:21 »
This is a perfectly normal graph. Those "fluctuations" are the actual variations of the potential with atomic resolution.
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2
General Questions and Answers / Re: Recommended Guideline for Creating a Ternary MTP by Combining Binary MTP
« on: September 24, 2025, 00:19 »
Quick check, do you really need Ge-Se-Te or Ge-Sn-Te (commonly, GST)? If it's the latter, we already have such a potential provided in the package.
Otherwise, you are in for a ride, but a potentially very rewarding one!
Your methodology is sort of correct, but you don't fit separately for 1-3, you combine those steps into one. That is, you include a bunch of basic crystal structures for all combinations in one training set (which you can test against the crystal experimental data). Then, instead of your step 4, you use active learning on a set of random alloys (and/or amorphous structures) of Ge-Se-Te to refine the potential for the full system. Ideally, for different stoichiometries! This is similar to the workflow we used for TiSi2 in the tutorial below, just a bit more complex for your case since you have 3 elements.
https://docs.quantumatk.com/tutorials/mtp-training-c-am-TiSi/mtp-training-c-am-TiSi.html
Otherwise, you are in for a ride, but a potentially very rewarding one!
Your methodology is sort of correct, but you don't fit separately for 1-3, you combine those steps into one. That is, you include a bunch of basic crystal structures for all combinations in one training set (which you can test against the crystal experimental data). Then, instead of your step 4, you use active learning on a set of random alloys (and/or amorphous structures) of Ge-Se-Te to refine the potential for the full system. Ideally, for different stoichiometries! This is similar to the workflow we used for TiSi2 in the tutorial below, just a bit more complex for your case since you have 3 elements.
https://docs.quantumatk.com/tutorials/mtp-training-c-am-TiSi/mtp-training-c-am-TiSi.html
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News and Announcements / Bugfix update QuantumATK X-2025.06-SP1
« on: September 13, 2025, 00:58 »
A small bugfix update QuantumATK X-2025.06-SP1 has been released.
Download the installers from SolvNetPlus as usual.
Fixed issues:
Download the installers from SolvNetPlus as usual.
Fixed issues:
- In rare cases, it was not be possible to create a project folder on some network drives on Windows
- The Jobs tool did not retain user preferences for script auto-start behavior and resets to default.
- In the Editor, using “Find” and “Replace all” to replace a word with itself caused NanoLab to freeze.
- QuantumATK X-2025.06 installation failed on ARM64 Windows machines with x86_64 binary support.
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Scripts, Tutorials and Applications / Re: ModuleNotFoundError for analysis modules (e.g., Analyser, ATK) in version X-2025
« on: September 13, 2025, 00:52 »
Where are these OrientationFunction and NematicOrderParameter functionalities supposed to come from? QuantumATK does not have those functionalities built in. You may have a separate script Analuyser.py which implements them, in which case you try
but that script then needs to be in the same directory as where you run.
Code
from .Analyser import *5
General Questions and Answers / Re: how to restart Defect MTP Training after interruption
« on: September 3, 2025, 03:18 »
In the normal case, the MTP training scripts are fully restartable. So just run it again in the same directory and it will pick up where it left off. But there are many details, so perhaps it doesn't always work...
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Scripts, Tutorials and Applications / Re: How to Apply Heat Flux in NEMD Simulations Using the "Exchange Interval" Option
« on: September 3, 2025, 03:14 »
The heat sinks need to be a bit bigger than just a few atoms, usually 4-5 layers is probably fine.
The other fundamental questions should be answered in the references under https://docs.quantumatk.com/manual/Types/NonEquilibriumMomentumExchange/NonEquilibriumMomentumExchange.html
The other fundamental questions should be answered in the references under https://docs.quantumatk.com/manual/Types/NonEquilibriumMomentumExchange/NonEquilibriumMomentumExchange.html
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General Questions and Answers / Re: CALCULATED CARRIER CONCENTRATION
« on: September 3, 2025, 03:11 »
Use density_of_states.calculateCarrierConcentration(...)
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General Questions and Answers / Re: Analyzing spin-resolved currents across different versions of QuantumATK
« on: September 3, 2025, 03:10 »
Frank, I missed this while on vacation. 2022 files should be fully compatible. It should be very easy to solve with a few lines of Python code, but would need a few more details, like if this is an IVCharacteristics object, or noncollinear calculations, etc. We can handle it over emails.
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General Questions and Answers / Re: Kerker Preconditioner for LCAO DFT calculations in X-2025.06
« on: September 3, 2025, 03:07 »
Don't use the Kerker preconditioner, I have never seen it give any benefits.
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General Questions and Answers / Re: Non collinear Spin Relaxation
« on: September 3, 2025, 03:05 »
Pls share input and output, else there is no way to tell if you made some simple mistake. But it is an old tutorial, so perhaps something needs updating, we can check.
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General Questions and Answers / Re: DFT Phonon Transmission
« on: September 3, 2025, 03:03 »
If you go to 1x1 then at least turn on the Wigner-Seitz scheme, else you are making a Gamma point phonon approximation. I would probably check if some of the machine-learned forcefields like MACE or M3GNet give at least decent phonon dispersions, and if so use them, for a much, much, much shorter calculation time, which hopefully is at least equally qualitative as a very approximate DFT simulation.
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General Questions and Answers / Re: Issue to apply uniaxial stress on built heterostructure properly
« on: September 3, 2025, 03:00 »
It's somewhat straightforward for a bulk crystal, but how the strain should be applied in a heterostructure is much more complex. I don't think it is enough to just change the axes A B or C, you need a more careful analysis, not least because of the lattice mismatch in the interface.
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General Questions and Answers / Re: RAMAN Spectrum on monolayer MoS2
« on: September 3, 2025, 02:57 »
Sorry, but it's an impossible question to answer short of myself running all calculations to check that every parameter is using correct sensible values (enough k-points, maybe needs more?), if the structure is correctly optimized (why not optimize the cell size?), etc, etc.
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General Questions and Answers / Re: Use cases of ChargedPointDefect vs. ChargedPointDefectConfiguration
« on: September 3, 2025, 02:55 »
Yes, that is the main difference. A new tutorial on this topic is in the works.
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General Questions and Answers / Re: HartreeDifferencePotential caculation
« on: September 3, 2025, 02:54 »
Maybe check the electron temperature, the default was 300 K when the tutorial was written, now it's 1000 K, maybe that causes convergence problems. We will also check ourselves if the calculation settings are still correct, the tutorial is 9 years old and some adjustments may be needed for newer versions of the code.