Question about the full relativistic pseudopotential

[jinghang_dai1]

Hi! I want to get the band structure of a semi-metal. The pseudopotential is only scalar relativistic. I want to do calculations using the full relativistic pseudopotential. But I cannot find it online. I wonder does VASP has full relativistic pseudopotential? Thank you so much! Looking forward to hearing from you.

Best,
Jinghang

[pedro_melo]

Dear jinghang_dai1,

The pseudopotentials are indeed generated using only the scalar relativistic equation. However, you are still able to perform relativistic calculations by activating the spin-orbit coupling in the INCAR.

Kind regards,
Pedro

[jinghang_dai1]

Thanks for your reply! Even though I can activate the spin-orbit coupling, the calculations VASP performs are still based on a scalar relativistic equation, am I right? In short, there is no way to perform full relativistic calculations in VASP, right?

[pedro_melo]

Dear jinghang_dai1,

No, VASP does not support full-relativistic calculations. Interactions like spin-orbit coupling are supported by including it as a perturbation to the Hamiltonian.

On a more elaborated note: I think you will find out that there are some papers, specially on materials like Bi2Se3, that there are some consequences from treating spin-orbit coupling as a perturbation vs exactly, both at DFT and GW level. See for instance https://doi.org/10.1103/PhysRevB.100.155147 and some related papers from the same authors. Please keep this in mind when analysing your results.

Kind regards,
Pedro