[Pw_forum] Au (111) Surface Energy

[Jack Davis]

Dear Ari,

Any other papers you can provide relating to this problem would be extremely useful. Thank you very much.

Best Wishes,
Jack Davis

On 15 Nov 2013, at 21:18, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi> wrote:


Dear Jack Davis,

 It is well known in the community that this is not a very accurate approach to calculate the surface energy, even if in principle correct (or, even the definition): You should at least make sure that the bulk is calculated along the (111) direction with the same k point sampling. Only if you are very well converged with the k point sampling in both the slab and bulk you might get a converged value. A classic article discussing this problem is

Vincenzo Fiorentini and M Methfessel 1996 J. Phys.: Condens. Matter 8 6525 doi:10.1088/0953-8984/8/36/005
"Extracting convergent surface energies from slab calculations"

 I can also try to find some more recent references if you wish.

   Greetings from Zurich,

      apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
 Ari P Seitsonen / Ari.P.Seitsonen at iki.fi<mailto:Ari.P.Seitsonen at iki.fi> / http://www.iki.fi/~apsi/
 Physikalisch-Chemisches Institut der Universitaet Zuerich
 Tel: +41 44 63 54 497  /  Mobile: +41 79 71 90 935


On Fri, 15 Nov 2013, Jack Davis wrote:

Dear Forum,

I’m trying to calculate surface energies using PWscf, however, I am unsure of the methodology. To begin with we calculate the bulk energy of the FCC unit cell, using the attached input. We then calculate the energy of a 111 slab, 10 layers thick with a 6 atom vacuum gap. The surface energy is then calculated as,

Surface energy = Energy of slab - (bulk energy * 10) / 2.

I think I am probably misunderstanding the energies PWscf is giving me. We’re getting some strange answers!

Thank you,
Jack Davis

School of Chemistry
University of Birmingham
_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org<mailto:Pw_forum at pwscf.org>
http://pwscf.org/mailman/listinfo/pw_forum