Page 1 of 1

bands in GW correction

Posted: Tue Apr 06, 2010 9:31 am
by yaser
Dear Abiniters,
In the first Tutorial on GW for Si ,
based on which rules the 4 and 5 bands ank kpt=(-0.1250 0.000 0.000 )have
been selected for determining the band gap ?
My Dear Abiniters ,please help me .
I am wating to your comments.
tank you
asadi.

Re: bands in GW correction

Posted: Tue Apr 06, 2010 10:42 am
by david.waroquiers
Hello,

The pseudopotential you are using for silicon uses 4 electrons as valence (you can see it in the pseudopotential file, second line, "zion"). The silicon system in the tutorial GW has 2 atoms per unit cell so you have 8 electrons in your systems. These 8 electrons fit in 4 bands (2 electrons per band) so the last occupied band is band number 4 and the first unoccupied band is band number 5 and the bandgap is defined as the difference between them.

David

Re: bands in GW correction

Posted: Wed Apr 07, 2010 10:31 am
by yaser
Dear David,

Thanks for your reply. That's helpful!

Best regards,
Asadi.