[Pw_forum] Work function issues

[Giovanni Cantele]

Maybe it is neither a poor pseudo potential choice nor a bug or user error.

Using for example Au.pbe-mt_fhi.UPF  I get

Fermi level ~ 3.30 eV
vacuum level ~ 8.48eV

with a plot similar to what you attach in a follow-up e-mail.
That corresponds to a ~ 5.17 gold work function, not that far from literature results, see, e.g., PHYSICAL REVIEW B 80, 235407 2009 .

Take care of slab thickness convergence issues as well as of the fact that a more accurate calculation might require a bulk crystal calculation,
see details in the above reported reference.

Giovanni
> On 21 Apr 2016, at 17:57, Hepplestone, Steven <S.P.Hepplestone at exeter.ac.uk> wrote:
> 
> Dear all,
>  
> I am having difficulties with calculating the work function of various metals (Au and Pt in particular) using the X.pbe-mt_fhi.UPF and X.pbe-n-nc.UPF pseudo potentials.  Unlike in the example in WorkFct_example in PP I am regularly getting a positive Fermi energy and a vacuum level which is lower than the average level for the potential of the atoms.  Is this a case of poor pseudo potential choice, a bug or user error?
>  
> Any advice would be appreciated,
>  
> Kind regards
>  
> Steven
>  
>  
> Dr. Steven Hepplestone
> Physics
> University of Exeter
> Stocker Road
> Exeter
> EX4 4QL
> Ext.: +44 (0)1392 723048
> Int.: 3048
>  
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-- 

Giovanni Cantele, PhD
CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy
e-mail: giovanni.cantele at spin.cnr.it
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: http://people.na.infn.it/~cantele

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