ABINIT Discussion Forums

Dear All,

In GW calculations, kptgw is the same with kpt. But kpt depend on ngkpt. So, how can we get the accurate band gap?

Take Si for example,

ngkpt 4 4 4

then,

kpt -1.25000000E-01 -2.50000000E-01 0.00000000E+00
-1.25000000E-01 5.00000000E-01 0.00000000E+00
-2.50000000E-01 -3.75000000E-01 0.00000000E+00
-1.25000000E-01 -3.75000000E-01 1.25000000E-01
-1.25000000E-01 2.50000000E-01 0.00000000E+00
-2.50000000E-01 3.75000000E-01 0.00000000E+00
-3.75000000E-01 5.00000000E-01 0.00000000E+00
-2.50000000E-01 5.00000000E-01 1.25000000E-01
-1.25000000E-01 0.00000000E+00 0.00000000E+00
-3.75000000E-01 0.00000000E+00 0.00000000E+00

But, the top of valence bands is at 0 0 0 and the bottom of conduction at 0.4 0.4 0. Both of them are not included in kpt. I do not know how it works. It would be very nice if you could give me some advices.

Thank you in advance.