ABINIT Discussion Forums

In your input, you have this line:


May I kindly suggest you to consider the consequences of increasing this value?


Fabien

1.34 eV is not that bad.

Difficult to help you without your input files...

Fabien

What is the value of nbandkss and kssform in your input file?
We'd all save time if you could provide full input files...
Cheers,

Fabien

The shifts you used do not yield a regular grid in the full BZ. nshiftk1 4 shiftk1 0.5 0.5 0.0 # These shifts will be the same for all grids 0.5 0.0 0.0 0.0 0.5 0.0 0.0 0.0 0.0 For your hexagonal cell, it is usually advised to use either a single shift nshiftk 1 shiftk 0.0 0.0 0.5 or even safer no s...

Please, check carefully that you didn't change the k-point set along with the different runs.
ngkpt, shiftk etc... should be the same in all the steps of the GW calculation.

Fabien

No, the k-points need to be regularly spaced in a GW calculation. The same is also true for the exact-exchange. So I don't know what VASP is doing for hybrid.

Fabien

Dear Yuanxun, nband is the number of bands to be used to calculate chi_0 if optdriver=3 or to calculate \Sigma_c if optdriver=4. nbandkss is the number of bands to be stored in the wavefunction file called KSS file. So that nband is always lower than nbandkss. ecutwfn is the cutoff energy used to tr...

For sure, the HGH pseudopotential is not compatible with the current implementation of the KSS generator. You should take a look at the header of the pseudopotential for Indium and discover how many electrons they consider as valence. 3 ? 13 ? or 21 ? For proper GW calculation, I'd bet that you need...

GW pseudopotentials should include semicore states. For Indium, I'd advise to have one including 4s, 4p and 4d as valence.
I guess the one you propose is not suitable.
Concerning oxygen, no problem.

Fabien

Does your pseudopotential for Zn consider 3s and 3p electrons as valence ? This is of the utmost importance for the final result. It has been published several times that G0W0 for ZnO, ZnS, and ZnSe underestimates quite much the experimental band gap. You may turn to self-consistent GW to improve th...

The writing of the KSS file is not yet compatible with the use of the parallelization paral_kgb=1.
The usual strategy is to run a parallel job to output a WFK file and then run a 'fake' sequential job that reads the WFK file and write the KSS file.

Fabien

Could you please provide an input file that demonstrates the problem?
Thanks.

Fabien

No the dielectric constant is calculated along one direction, which is supposed to mimic the averaging...
By default, the direction is (123). I think I remember you can change this value by specifying the keyword "qptdm".
Let us know if this is still working.

Fabien

Due to the non-locality of the exact-exchange and of the self-energy operator, there is no possibility to avoid the use of a regular grid within GW. My advice to obtain the GW band structure is to perform the GW corrections for all the the k-points in the full Brillouin Zone and then perform a Fouri...

Hello,

I think this message is not really robust. You should not carry too much attention to it.
Just make sure that your eigenvalues/wavefunctions are well converged within the CG technique.
Sorry for this sloppy reply.

Fabien