Surface Si(111) Hydrogen terminated + Molecule

[Oscar_rp]

Dear Vasp Users

I have a problem when I plot the band structure for a system consisting in a Silicon 111 surface with H terminaed and a molecule bound to the surface.
I used the ISMEAR = 0 to calculate the DOS and the band structure with a grid of 8x8x1
for the surface+molecule and for the system with the clean surface.
Later I have changed the KPOINTS file to the following file
to get the band structure. Linre L-G-X...etc

K-Points
10
Line-mode
reciprocal
0.5 0.5 0.5 1
0.0 0.0 0.0 1

0.0 0.0 0.0 1
0.0 0.5 0.5 1

0.0 0.5 0.5 1
0.25 0.6250 0.625 1

0.375 0.75 0.375 1
0.0 0.0 0.0 1

In the system of surface+molecule I have two horizontal lines just exactly at the band edges of the band gap, which I do not understand and it is crossing the highest occupied band at the Gamma (G) point. Is there anything I have done in wrong way?


Many thanks in advanced
Oscar R.

[forsdan]

You can't sample a 3D Brillouin zone for a 2D structure. Please notice that the perpendicular k-component no longer is a valid quantum number since the periodicity is broken in that direction. So please do a proper sampling of the surface Brillouin zone.

Also, I question if the weight can be specified in line-mode. There is nothing in the manual about it.

Cheers,
/Dan

[Oscar_rp]

Thanks, Dan, Now I understand what I did worng, but I have not found the solution. You are right, the K points used are for the Si bulk, and not for a surface. Could you point me in the right direction.

Thanks in advanced