[Pw_forum] How to get the usual ~2.4 eV band gap of ZnO with HSE06?

[Nicola Marzari]

On 11/08/2017 15:10, Tan Hengxin wrote:
>         My value is just ~2.1 eV.
>         Maybe my norm-conserving pseudopotentials (NC-PPs) of Zn and O
>         are not very good. So I also tried the NC-PPs for Zn and O from
>         the pslibrary.0.3.1. However, the gap is even smaller (~1.8 eV).
>         (All PPs are based on PBE xc.)


This already tells you that the pseudopotentials are certainly a 
problem. You might have also other problems, of course - but these are 
one. Where do the original ones come from? (the ones that give you 2.1)?

After having seen the SSSP tests I would try the Zn and O from SG15, at 
~100 Ry: http://www.quantum-simulation.org/potentials/sg15_oncv/

Can you report what you get?

Thanks,

			nicola

-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project