[Pw_forum] About Surface energy convergence

[Giovanni Cantele]

I had a (VERY QUICK!) look at the paper you mention. Actually, they make a convergence study, with respect to the number of  Au layers, more complicated than just looking at the surface energy. For example, they do analyze magnetic moments, as well as relaxation of the inner and outer atomic layers. In that case they conclude that 11 Au layer must be considered. So, you should carefully look to the convergence of also structural and electronic properties. Another parameter that might be chosen as a reference for convergence thresholds is the metal work function. In this respect, you can find a detailed discussion of metal surfaces convergence properties for example in PHYSICAL REVIEW B 80, 235407 2009 (and references therein).

In the specific case of the system you are studying, you might be interest in the convergence of the interface properties as well. You can find some more details specific of ZnO-metal interfaces for example in J. Phys.: Condens. Matter 27 (2015) 015006 (and references therein).

Giovanni

> On 20 Jan 2016, at 06:42, Bipul Rakshit <bipulrr at gmail.com> wrote:
> 
> Dear PWscf Users,
> In surface studies,for the slab calculations, the number of slabs is chosen with the convergence of Surface energies. So what is the typical convergence value I have to choose. I find some papers where the authors choose upto 5 milli-J/m^2 (PRB 86, 075460 (2012). They  take the case of Fe(001)/Au(001). These are basically the cubic structure.
> 
> What about the bit more complex structure like Zn(0001)/Au(111), where the lattice mismatch is considerable and the structures also. Is the ~5 milli-J/m^2 accuracy essential, or we can set some upper limit of this convergence value.
> 
> -- 
> Dr. Bipul Rakshit
> Research Associate,
> Institute of Physics (IOP),
> Bhubaneswar- 751 005
> Orissa 
> India
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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