QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: maj7293 on July 18, 2022, 15:52

Title: Strange results in Te (Tellurium) atom
Post by: maj7293 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.

Title: Re: Strange results in Te (Tellurium) atom
Post by: Dongzhe on August 15, 2022, 07:57

Hi,

There are two things that might be important:
1. Your results depend on your DFT Hamiltonian (basis sets, functional, DFT+U...). So, better to first check whether you can reproduce well the band structure of VTe2 compared to the literature.
2. The methodology for calculating the HeisenbergExchange constant might be different. The QATK uses Green's function approach which treats the spin rotation as a perturbation. There are also other methods such as the spin spiral approach (based on the generalized Bloch theorem) and the supercell approach, often used in the literature. Different methods can probably give different results. However, in many cases, we expect to have a qualitative agreement.

Best regards,
Dongzhe