SCF does not converge for ZnO slab

[donniedarko]

Hi,

I have a problem converging a in my eyes fairly simple slab structure. The structure is a ZnO slab:

Zn O
1.0000000000000000
3.2909990940830092 0.0000000000000000 0.0000000000000000
-1.6454995470415046 2.8500894957131062 0.0000000000000000
0.0000000000000000 -0.0000000000000000 37.1257455150137687
4 4
Direct
0.3333330000000032 0.6666669999999968 0.4556748981770778
0.6666669999999968 0.3333330000000032 0.3842463267485064
0.3333330000000032 0.6666669999999968 0.5985320410342206
0.6666669999999968 0.3333330000000032 0.5271034696056492
0.3333330000000032 0.6666669999999968 0.4014679589657794
0.6666669999999968 0.3333330000000032 0.4728965303943508
0.3333330000000032 0.6666669999999968 0.5443251018229223
0.6666669999999968 0.3333330000000032 0.6157536732514937

and the INCAR reads:

EDIFF = 1.00e-07
EDIFFG = -5.00e-03
PREC = Accurate
GGA = PE
ISMEAR = -5
NELM = 100
IBRION = 2
NSW = 0
LREAL = Auto

However, the scf-cycle does not converge. As suggested in https://www.vasp.at/vasp-workshop/slide ... ectron.pdf I tried using ICHARG = 12 which lead to convergence. Yet when using ICHARG = 2 and playing with the mixing parameters the calculation again did not converge. I also tried ALGO = Fast, and different combinations of AMIN, AMIX, and BMIX. The employed KPOINT mesh is 5x5x1.

If you have any suggestions on how to converge this simulation I would be very grateful!

Daniel

[admin]

Predefined spin state (NUPDOWN=0) will help