[QE-users] Fwd: Problem in band gap calculation

[pboulet]

Dear Neelam,

The result you got is not related to the pseudopotential but to the functional you used or to the structure. 

We calculated some properties of Zn(1-x)Cd(x)Sb  some years ago (FYI: CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 35 (2011) 639–642).

We got a band gap of about 0.18 eV with PBE and NC-PSP.  First: are you sure your structure is the good one? You should have a small band gap around 0.2 eV…

I guess that, in the works you are referring to, the people were using a different strategy to get a higher band gap: DFT+U? Hybrid functional? TBm-BJ potential?

Best,
Pascal

Pascal Boulet
—
Professor in computational materials - DEPARTMENT OF CHEMISTRY
University of Aix-Marseille - Avenue Escadrille Normandie Niemen - F-13013 Marseille - FRANCE
Tél: +33(0)4 13 55 18 10 - Fax : +33(0)4 13 55 18 50
Email : pascal.boulet at univ-amu.fr <mailto:pascal.boulet at univ-amu.fr>




> Le 8 mai 2020 à 13:10, Neelam Swarnkar <neelamswarnkar35 at gmail.com> a écrit :
> 
> 
> ---------- Forwarded message ---------
> From: Paolo Giannozzi <p.giannozzi at gmail.com <mailto:p.giannozzi at gmail.com>>
> Date: Fri, May 8, 2020, 2:23 PM
> Subject: Re: Problem in band gap calculation
> To: Neelam Swarnkar <neelamswarnkar35 at gmail.com <mailto:neelamswarnkar35 at gmail.com>>
> 
> 
> Please write to the mailing list, not to me
> 
> On Fri, May 8, 2020 at 10:24 AM Neelam Swarnkar <neelamswarnkar35 at gmail.com <mailto:neelamswarnkar35 at gmail.com>> wrote:
> Dear Owner
> 
> I am new in Quantum espresso calculation, I want to calculate band gap of semiconductor type of material ZnSb , but by using PAW PBE pseudopotential file, i am getting the band gap like a metal material mean band gap overlapped. 
> 
> So i think , i have taken wrong pseudopotential.
> 
> many other author reported the band gap of ZnSb=0.72 eV or in other paper it is =0.53 to 0.61eV 
> 
> so, please suggest me, what type of pseudopotential have to choose for semiconductor band gap calculation.
> 
> Regards
> 
> Neelam Swarnkar
> Phd scholar
> 
> 
> On Fri, May 8, 2020, 1:37 PM Paolo Giannozzi <p.giannozzi at gmail.com <mailto:p.giannozzi at gmail.com>> wrote:
> I have already answered and you ignored my message: DO NOT SEND LARGE ATTACHMENTS, IN PARTICULAR DO NOT SEND PAPERS. 
> 
> On Fri, May 8, 2020 at 9:53 AM Neelam Swarnkar <neelamswarnkar35 at gmail.com <mailto:neelamswarnkar35 at gmail.com>> wrote:
> Dear owner
> 
> Please , permit me to send mail in this group.
> 
> 
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
> 
> 
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
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