Messages

1

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

« 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!

2

Scripts, Tutorials and Applications / Magnon dispersion

« on: January 25, 2024, 12:13 »

Dear all,

I am using the Quantum ATK 2021-06 version and I have calculated the Heisenberg exchange coupling constants and plotted the magnon dispersion. I would like to know the procedure of mapping the model to DFT. Particularly, my question is:  does ATK include the magnetic anisotropy energy in its calculations in plotting magnon dispersion? if yes, how? I mean using the anisotropy term in the Heisenberg spin model or is it affected by the DFT calculations on Jij parameters?

I would be very grateful if you could give me a hint.

Thank you.

3

Scripts, Tutorials and Applications / Calculate the magnetic moment for PAW calculations

« on: August 17, 2023, 17:01 »

Dear all,

I have calculate the Spin orbit calculations of Eu using PAW calculator (SO-GGA) and I need now to calculate the magnetic moment per atom but ATK doesn't have the module for calculating MullikenPopulation. Is there anyone to help me how can I calculate the magnetic moment for this type of calculations?

* Of course if anybody know how can I find the fully relativistic pseudo potential for LCAO calculator, I will be appreciated.

4

General Questions and Answers / Strange results in Te (Tellurium) atom

« on: July 18, 2022, 15:52 »

Dear All,

I have a problem with calculating the HeisenbergExchange constant (J1 and J2)  for the VTe2 monolayer which gives a very small value. However, according to the papers, it should be higher than the other materials (e.g. VS2, VSe2 ). I also should note that the other properties are reasonable.

Is there anyone to know what is the problem?
Thank you.

5

General Questions and Answers / Re: Heisenberg exchange: QuantumATK T-2022.03

« on: April 15, 2022, 12:45 »

I checked with the older version and it is OK there. As you guessed it probably is a bug from the newer version.
I attached the output file. 

6

General Questions and Answers / Re: Heisenberg exchange: QuantumATK T-2022.03

« on: April 12, 2022, 19:04 »

Dear Dongzhe,
It seems that you've used two separate calculators in your script generator. Could you put your input to check?

7

General Questions and Answers / GGA+U

« on: April 12, 2022, 17:32 »

Hello.
I have a problem with using the GGA+U calculation to find the Heisenberg exchange coupling. Without using GGA+U for the V atom the results are reasonable but with applying U=2 (from the literature) the results (e.g. BS, Jij and ... ) are significantly different. Why does it happen?
I would be thankful if someone help me.
I am using the quantumatk/P-2021.06-SP2.