[Pw_forum] about fermi level

[Haruhiko Dekura]

Dear Wang 

I think that the Fermi-level obtained with nscf run reaches sufficient value only when the KS energy spectrum ( hence, also scf-potential ) is well converged in scf calculation. 
Therefore, in my guess, if you can see the convergence of KS levels as well as total energy against the increase of k-point (and width of smearing), the Fermi-level obtained with DOS calculation is more reliable value. So, I think the problem is depending on the convergency of your scf-potential after scf calculation. If you don't have converged one,  both Fermi-levels ( obtained by scf or nscf run) so obtained are both not sufficient.          
What do you think ?


Haruhiko Dekura

PH.D. student
Osaka university 


On 2009/12/29, at 23:51, Q.J.Wang wrote:

> Dear all
>      After I run scf(k-points,3*3*3)with 'smearing'  , I increase the k-points (5*5*5)and run nscf with 'tetrahedra' in order to get DOS,but the fermi levels have little difference between the scf.out and nscf.out . Which I should select when plot DOS pictuce ?
>      I have search in the forum ,but still haven't the correct answer .
> --
> Best regards
>  
> Q.J.Wang
>  
> XiangTan University
> 
> 
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