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Bandstructure by hybrid functional

Posted: Tue Dec 21, 2021 1:20 pm
by IBRAHIM
Dear All,

For calculation of bandstructure using hybrid functional, I follow the procedure 2 of vasp wiki wiki/index.php/Si_HSE_bandstructure

1- standard DFT
2-hybrid calculation with wavecar (rocommend to be from step and not from hybrid calculation) and modified KPOINTs file

My question is that: is it possible in step 2 to allow also ionic relaxation by provide NSW>1. Most researcher use NSW=0. Howvere, aditional ionic relaxation by hybrid functional may also affect.

Many thanks in advance,
Ibrahim

Re: Bandstructure by hybrid functional

Posted: Fri Dec 24, 2021 2:25 pm
by SKM
hi
i did not do this way, as i mostly link hybrid functional i.e. HSE06 with Wannier90 option. So, i cannot give much tech input for your specific problem. Based on the method i follow, i can guess some answer to your query.

in my view: [someone correct me, if my perception is wrong]
if you want to do ionic relaxation, either you may do the standard DFT itself with hybrid functional tags. or after standard DFT, repeat the run with Hybrid functional, taking the CONTCAR from previous DFT run.

But you should NOT combine, band structure calculation with NSW>0 and its wasting resources.

Regards

Re: Bandstructure by hybrid functional

Posted: Fri Dec 24, 2021 6:38 pm
by fabien_tran1
Hi,

To optimize the geometry also with HSE or not, depends on the importance of geometry for your final goal (does the considerd property depend sensitively on the geometry) and the computational cost it involves (can you do it in a reasonabe amount of time?).

From the technical point of view, NSW>1 should work.

Re: Bandstructure by hybrid functional

Posted: Mon Dec 27, 2021 6:31 am
by IBRAHIM
Thank you very much.