ABINIT Discussion Forums

Dear All,

I calculate band gap of Si crystal. When I use some high K-point, for example 12*12*12, I can not get any band-gap value with GW correction. But the calculation seems to be successful. Where is the problem? It would be very nice if someone could give me some suggestion. Thank you in advance.

Regards,

Wang

Hello,

Without your input file and part of the out or log file, it is difficult to help you. Have you checked that the k-points for which you ask the gw correction are contained in your high k-point mesh ? I guess so because otherwise abinit would complain but well.

If you post your input file (at least), we might help you more.

David

The following is the input file:

optdriver 4
nband 100
ecutsigx 17
ecutwfn 17

gwcalctyp 28

nkptgw 8
kptgw
0.00000000E+00 0.00000000E+00 0.00000000E+00
2.50000000E-01 0.00000000E+00 0.00000000E+00
5.00000000E-01 0.00000000E+00 0.00000000E+00
2.50000000E-01 2.50000000E-01 0.00000000E+00
5.00000000E-01 2.50000000E-01 0.00000000E+00
-2.50000000E-01 2.50000000E-01 0.00000000E+00
5.00000000E-01 5.00000000E-01 0.00000000E+00
-2.50000000E-01 5.00000000E-01 2.50000000E-01
bdgw
1 30
1 30
1 30
1 30
1 30
1 30
1 30
1 30

#Definition of occupation numbers
occopt 1
#tsmear 0.01

#Definition of the unit cell
acell 3*10.259

rprim 0.0 0.5 0.5 # FCC primitive vectors (to be scaled by acell)
0.5 0.0 0.5
0.5 0.5 0.0

#Definition of the atom types
ntypat 1
znucl 14

#Definition of the atoms
natom 2
typat 1 1
xred 0.0 0.0 0.0
0.25 1.25 0.25
#Definition of the planewave basis set
ecut 20.0

#Definition of the k-point grid
ngkpt 12 12 12
nshiftk 1
shiftk 0. 0. 0.
istwfk 72*1

#Definition of the SCF procedure
nstep 50
toldfe 1.0d-10

prtvol 5
enunit 1

The kptgw is wrong? I am the freshman about GW calculation. Please help me to check it. Thank you!

Regards,

Wang

1) David asked you for your log file...
2) Your k-points are over-over-converged.

Fabien

Thank you for your response.

1)Attached please find the output file.
2)Generally, K-points with 12*12*12 is used in literature. So, How should | choose K-points? Only depending on the converged test?


Wang