Recent Posts

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21
General Questions and Answers / Update - Stress outliers in TrainingSet
« Last post by AsifShah on June 12, 2026, 02:41 »
Dear All,

I use an optimization trajectory to relax the interface between two materials, A-B, and then use it to fine-tune the MACE model.
However, there are some high-stress outliers in the optimization trajectory.
I would like to know how to delete such high-stress outlier images and save a new trajectory.


Thank you
22
Scripts, Tutorials and Applications / Seeking the tutorial for the Defect Diffusion Workflow Template
« Last post by Ada_Lee on May 26, 2026, 09:42 »
Hello everyone,
 
I am studying the manual of quantumatk's SMW and I am attempting to utilize the Defect Diffusion workflow template. May I ask if there are any tutorials on Defects and Defect Diffusion worklow template?

Best regards,
Ada
23
General Questions and Answers / LDOS from VASP ProjectOnSite
« Last post by job314 on April 28, 2026, 03:07 »
Dear all, I am still trying to visualize VASP PDOS (or LDOS). I calculate them in VASP, but when I try visualizing, I am getting the message attached, e.g "LDOS requires one of the following projections: ProjectOnSite, ProjectonShellBySite, ProjectIOnOrbitalsBySite.

I am confused - did I not specify something in VASP - I did LORBIT=11 which calculates LDOS. What is QATK asking or telling me here, how do I visualize these LDOS?

thank you

Jonas
24
General Questions and Answers / How to obtain the magnetic moment per atom in QuantumATK U-2022.12-SP1?
« Last post by q_mechanic on April 24, 2026, 20:53 »
I am using QuantumATK U-2022.12-SP1 (Windows 11). One way to obtain the magnetic moment per atom of a bulk configuration is to use, for example, the LCAO calculator with a norm conserving (NC) pseudopotential and attaching a MullikenPopulation analysis tool. I am not too versed in the physics of obtaining Mulliken populations, but in this version, this tool is not supported for a PAW pseudopotential. Unfortunately, LCAO-NC does not yield good, physical results for the material I am working with (which happens to be a collinear magnetic material, by the way), whereas LCAO-PAW does, so using MullikenPopulation is out of the question.

Searching on the QuantumATK forum, Anders Blom has suggested here that one can use a PlaneWave calculator instead (which fortunately yields the correct band structure for my material, for example), alongside with a BaderCharge analysis tool, which is available for me. However, no further description is given. Therefore, how can I obtain the magnetic moment per atom using the PlaneWave calculator (or a work-around using LCAO-PAW)?
25
General Questions and Answers / HeisenbergExchange
« Last post by PedroSousa on April 7, 2026, 13:49 »
Dear all,

I have been using the HeisenbergExchange analyzer in QuantumATK (Version X-2025.06-SP1) to calculate the magnetic exchange parameters (J_{ij}) for several materials. So far, I have followed the workflow below to extract the (J_{ij}) values:

1. Using QATK I create and run a Python script to perform the LCAO and HeisenbergExchange calculations, storing the results in an `.hdf5` file.

2. I then open `atkpython` and use the following code to extract the exchange parameters:

   ```
   he = nlread(filename, HeisenbergExchange)[0]
   d, j, n = he.uniqueCouplingMatrixElementsAndDistances()
   ```

   where `j` is a vector containing the (J_{ij}) values in meV.

This approach has worked well for several systems. However, when applying it to hexagonal Fe₃C, the resulting `j` vector contains very small values for a ferromagnetic material. The largest value obtained is approximately 1.33 meV.

On the other hand, when I open the `.hdf5` results file directly in QuantumATK, the (J_{ij}) values shown in the GUI are significantly larger and appear physically reasonable (see attached image).

I would like to understand the origin of this discrepancy and how to correctly extract the full set of (J_{ij}) values consistent with what is shown in QuantumATK.

Thank you in advance for your help.

Best regards,
Pedro Sousa
26
General Questions and Answers / Re: Define a custom dictionary for NRLTightBindingParameters
« Last post by sukhito teh on April 3, 2026, 22:42 »
Can someone help me with this problem? I am using QATKV-2023.12-SP1. I think the on-site potential used in NRLHamiltonianParametrization cannot be reproduced in SlaterKosterHamiltonianParametrization.
Thank you.
27
General Questions and Answers / Re: Finetuning MACE
« Last post by AsifShah on April 1, 2026, 03:06 »
Update:

Turns out increasing Energy/Force/Stress weight in the 2026 version causes this error, at least for my model.
Restricting weights to 30 with learning rate of 0.001 gave excellent finetuned models.


28
General Questions and Answers / Fat Band Structure
« Last post by Jahanzaib on March 27, 2026, 23:07 »
Dear Experts,
I am currently working on calculating the fat-band structure of my system and would like to analyze the electronic states around the Fermi level. In particular, I am interested in identifying which Ni (d) orbitals overlap with Sn (p) orbitals for both spin-up and spin-down channels.

I would also like to know whether it is possible to estimate the percentage contribution of each orbital character from the fat-band analysis.

For reference, I am using the following code:

# -------------------------------------------------------------

# Fat-band structure

# -------------------------------------------------------------

fat_bandstructure = FatBandstructure(
configuration=configuration,
route=['G', 'Z'],
points_per_segment=20,
bands_above_fermi_level=All,
projections=ProjectionGenerator(
atoms=ElementsProjection,
l_quantum_numbers=True,
spin=UpDownProjection,
),
)

nlsave('fat-bs.hdf5', fat_bandstructure)

I would appreciate any guidance or suggestions on how to extract and interpret this information.


29
General Questions and Answers / Re: Difference Between electrode_extension_lengths and equivalent_electrode_lengths
« Last post by Anders Blom on March 27, 2026, 19:55 »
Check the Tip in https://docs.quantumatk.com/intro/intro_tutorials/electron-transport-Si-p-n/electron-transport-Si-p-n.html and see if that answers your question
30
General Questions and Answers / Re: changing display format in builder
« Last post by Anders Blom on March 27, 2026, 19:52 »
I don't think there is a keyboard shortcut to switch the rendering mode, so you might have accidentally hit a bug (which was more usual in the past) where atoms turned into single dots.

I personally hate the advice to "just reboot", but graphics settings are not persistent, so next time you start Nanolab all should be back to usual :-)

Otherwise the Graphics settings are in the right-hand add-on panel in the Builder.
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