Recent Posts

1

General Questions and Answers / Module "calculatePlasmaFrequency"

« Last post by sukhito teh on Yesterday at 15:33 »

Dear developers and users,
Does the function calculatePlasmaFrequency returns plasma frequency or square of plasma frequency? The formula in documentation https://docs.quantumatk.com/manual/Types/OpticalSpectrum/OpticalSpectrum.html#opticalspectrum-c uses ω², but the return value has unit of energy. Thank you for your attention.

2

General Questions and Answers / Re: Graphene layer over WSe2

« Last post by techenthusiast on April 4, 2025, 07:35 »

This is nice concept.
But in addition to your points -I have one question - How can the coat or surface modification of CNT be done using PubChem CID based external molecules? (You can give just points as steps)
N.B: I already know how to extract the molecules from PubChem CID after that you can guide. Thank you

3

General Questions and Answers / Graphene layer over WSe2

« Last post by muhammadishaq on April 4, 2025, 01:00 »

Hi all,

I hope you're doing well.

I am currently investigating the proximity effect between graphene and a WSe₂ layer, specifically looking for the band gap opening in graphene due to interaction with the WSe₂ substrate. However, despite several attempts and different approaches, I have not been able to observe the expected band gap in my calculations.

I’ve attached:

A band structure figure for your reference

The geometry optimization script

The band structure calculation script

Could you please take a look and let me know if you notice any issues or have suggestions for what might be going wrong?

Your feedback would be greatly appreciated! Thanks

4

General Questions and Answers / Search (Materials Project) not work with legacy API in ATK 2019

« Last post by berlin on April 3, 2025, 13:56 »

I am using ATK 2019, 

Recently, I found that using the Materials Project plugin is causing error:

REST query returned with error status code 403. Content: b' {"error“:  "You are trying to use the deprecated legacy API. Flease read our documentati on (https://docs.materialsproject.org) and upgrade to the latest version of the mp-api client (https//pypi.org/project/mp-api/)，"version”: "blocked"}'

How can I update this plugin? note that it is Unable to obtain a list of available add-ons now for ATK 2019 .:

The exception message:
HTTPConnectionPool(host='repository.quantumwise.com', port=80): Max retries exceeded with url: /2019.03/manifest.json (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0x0000022D7ADE1828>: Failed to establish a new connection: [Errno 11001] getaddrinfo failed',))

Is there a way to download the updated ZIP file and update it manually?

5

General Questions and Answers / Re: Source Exhaustion Effects

« Last post by techenthusiast on April 2, 2025, 06:46 »

Dear Experts,

Is there any effects, in such cases for different VDS studies?

For example for the same device VDS=0.1,1.0,0.8?
How should it behave as IV Analyzer?


Why 0.05V VDS is not working for GAA CNT FET -- Does not provide suitable ID -VGS

6

General Questions and Answers / Builder

« Last post by Lil_David on April 1, 2025, 23:30 »

Hello Everyone,

My stash panel and filter panel are not showing on my "builder." Please, what can I do to restore them? I have tried the restore builder layout and also restarted my quantumatk but the issue is not resolved.

Please, I will really appreciate a response; no one responded to my last question on Crystal Builder.

Thank you

7

General Questions and Answers / Source Exhaustion Effects

« Last post by techenthusiast on April 1, 2025, 07:51 »

Dear Experts,

Good morning, hope you are doing well. I have gone through these articles. Here they have mentioned Source Exhaustion Effects. I am enclosing my device structure so that can be comparable with the provided device structure at the literature. Especially for single channel device.  is it correct , the device structure?

https://sci-hub.st/10.1109/iedm.2009.5424281

https://ece.uwaterloo.ca/~l28wei/publications/2011TED_CNT.pdf

8

General Questions and Answers / Re: Effective bandstructure that goes beyond quantuamatk limitation

« Last post by sukhito teh on March 31, 2025, 09:26 »

1. Yes, memory, and you found the right solution - more threads rather than more MPIs per node reduces memory usage but keep the speed roughly the same, in many cases.
2. There are two guides in the manual around performance/parallelization and memory usage:
https://docs.quantumatk.com/manual/technicalnotes/parallelization/parallelization.html
https://docs.quantumatk.com/manual/technicalnotes/advanced_performance/advanced_performance.html
It's hard to give a single advice that works for all systems, but QuantumATK speeds up very well to high count of cores, and the more memory you need, the more you should rely on threading rather than MPI.
3. To me this is a very natural part of the projection algorithm, not least considering the way QuantumATK uses atomic orbitals as basis. It also provides a logical way to interpret the results. If your larger system is not really an extension of something with a smaller periodicity, the effective band structure may not be the best tool to analyze the results. The band gap for any system can always be inferred from the density of states, and the curvature is the same as the effective mass basically, which can also be computed directly for the supercell system.

Thank you for your reply.
1. You are right, the effective bandstructure that I had obtained is indeed very disordered due to poor symmetry.
2. Thanks, I would look into the effective mass module.

9

General Questions and Answers / Query Regarding Crystal Symmetry and Space Group Identification in QuantumATK

« Last post by UtpalLab123 on March 27, 2025, 20:07 »

Dear Sir/Ma'am,

When I compute the crystal symmetry and space group number for my system (plane 2d system), I see an option in the QuantumATK-R-2020.09-SP1 version called "Crystal Symmetry Info." Under this, there are two parameters:
(a) Position, which defines the tolerance of the fractional coordinates when searching for the space group.
(b) Angle, which defines the tolerance of the angles when searching for the space group.
My question is: What values should I use for these parameters to accurately identify the crystal symmetry and space group number?

10

General Questions and Answers / Re: Can we create MTP with dopant atom included?

« Last post by Lim changmin on March 27, 2025, 15:11 »

Thank you for your response.

I am currently working on training an MTP exclusively for amorphous structures, as there is no corresponding crystalline phase.

I have some questions regarding Step 1 of the standard crystalline training protocol. For training amorphous structures, active learning requires both MTP training and a training set generation function. In this process, MTP training is typically initialized using the random displacement function applied to a crystalline structure.

My question is: Can the crystal random displacement function be used for amorphous structures as well? Or is it strictly applicable to crystalline phases?

I am asking because, in the tutorial (https://docs.quantumatk.com/tutorials/mtp_hfo2/mtp_hfo2.html), the workflow in Step 1 explicitly refers to the "bulk phase." I am a bit confused by the term "crystal" in "crystal training random displacement function" and whether it applies to amorphous systems.

I would appreciate any clarification on this.