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Topics - NW

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1
General Questions and Answers / charged_defects
« on: July 26, 2022, 15:23 »
Hello,

I have a question regarding the following tutorial about charged defects formation energy.
https://docs.quantumatk.com/tutorials/charged_defects/charged_defects.html

It is mentioned that "E_VBM is the valence band maximum as given by the ATK band structure calculation for the bulk material of study". My question is how QATK takes VBE? because if we draw the bandstructure via the available tool for that in QATK, then automatically the Fermi energy is set at zero and all the bands are shifted accordingly. So the printed VBE is not the absolute VBE and it is VBE+E_fermi shifting. Am I right? if yes, how one can determine the correct value for VBE via QATK for charge defect calculations?

Thanks

2
General Questions and Answers / DFT-1/2 default parameters
« on: August 26, 2021, 09:52 »
Hello,

I have a question regarding DFT-1/2 default parameters for each element. Since we need to consider the surrounding atoms of specific element in each compound, I was wondering how QuantumATK deals with that. Does it considere default values for each element regardless of the surrounding atoms or it automatically adjusts the parameter based on the surrounding atoms?

Thanks,

3
Hi,

I need to know how to choose the correct number of k-point (kA and kB) for calculation of transmission spectrum.

Thanks

4
General Questions and Answers / Spin transport
« on: August 18, 2020, 14:45 »
Hello,

I have a question related to the following tutorial:

https://docs.quantumatk.com/tutorials/fe_mgo_fe/fe_mgo_fe.html

In the calculation part, the Hubbard parameter (U) was not used for Fe. Is there any reason for that?

Thanks

5
Hello,

Is it possible to use Monte Carlo simulation for calculating the exchange couplings in QuantumATK?

6
Hello,

Is it possible to calculate optical properties of a system by using Tags option?
For example for a system consisting of two layers, I want to calculate the optical properties of just top layer.

7
General Questions and Answers / refractive index of graphene
« on: April 20, 2020, 23:31 »
Hi,

I used GGA and HSE06 to calculate refractive index of graphene. The results show approximately n=1.7 for visible light range. In this reference [https://aip.scitation.org/doi/10.1063/1.3475393] n has been calculated experimentally and it was equal around 3. I attached my scripts here.
Is there any parameter that should be changed?

Thanks

8
General Questions and Answers / Vasp bandstructure in VNL
« on: April 13, 2020, 14:19 »
Hi,

I tried to draw the bandstructure obtained via VASP in VNL. I got the attached error. Could you please help me to fix the issue?
I attached the EIGENVAL file here.

9
Hello,

I calculated the band structure of bilayer graphene and the results with the script file were attached here. When I zoomed on the bands near to Fermi energy, it is clear that the Fermi level is not somewhere between the valance and conduction bands. How can I set the Fermi energy in the gap of the bilayer?

Thanks

10
Hello,

The last version of QuantumATK (2019.12-SP1) cannot be downloaded. I tried several times and got the following errors:

HTTP/1.1 404 Object Not Found

The requested URL was not found on this server.

Please fix the issue.
Thanks.

11
General Questions and Answers / Projection on n quantum number
« on: December 19, 2019, 18:05 »
Hello,

As I read on the following link, we can use Projection on l and m quantum numbers.
Is it possible to use projection function for n quantum number too (e.g. n_quantum_numbers=[5])?

https://docs.quantumatk.com/manual/Types/Projection/Projection.html

Thanks,

12
General Questions and Answers / NPT calculation
« on: November 18, 2019, 13:15 »
Dear ATK experts,

Is it possible to consider NPT calculation in MD for slab configuration?
Because I need to decrease the pressure in my system up to 10**(-10)mbar but I have a slab system.

Thanks for your help.

13
General Questions and Answers / Phonon bandstructure
« on: September 10, 2019, 12:50 »
Hello,

I am looking to find a way to reducing RAM occupation when I am running Phonon bandstructure calculation. I access 100Gb RAM, however when I run my simulation I got an error related to shortage of RAM capacity.
I changed the parameters in my input script but still I need to find a way to reduce RAM occupation. If it is possible, please let me know how I can modify the Dynamical Matrix block for possible performance on my computer. I used DFT for my aim in ATK 2019.3.

Thanks for your support.

14
Hi,

In the output of Mulliken Population for Noncollinear calculation, we can find the total Spin Magnetic Moment. What is the unit of the value? is it atomic unit or SI?

Thanks

15
Hello,

I am looking to find a way to connect ATK 2019-03-SP1 to license server via command line in linux. I know that it is possible very easy via graphical interface but I cannot access it in my machine. Please help me to do that in linux terminal.

Thanks

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