[Pw_forum] Si diamond-cubic to beta-Sn transformation

[Daryl Chrzan]

Michael,

Thank you for the response.  I agree that I am far from the minimum.  However, when I do get to the minimum, I end up with a c/a ratio that is far off, and an energy difference of 0.6 eV, about twice what you find.  (I have, I believe, accounted for the proper number of atoms, etc.)  

I have done the calculation with the PAW potential and the PZ-vbc potential and obtained the same results.  Obviously I am doing something wrong but I simply cannot see it.  I'll try the Si.pbe-n-van.UPF and see if I can reproduce your 0.29 eV energy difference.  Did you c/a work out to be around 0.547?

Daryl

Daryl C. Chrzan
Professor, Materials Science and Engineering
University of California
Berkeley, CA 94720

and

Materials Sciences Division
Lawrence Berkeley National Laboratory
Berkeley, CA 94720

ph./fax: 510 643 1624