Problem convergence Bi2Se3 surfaces

[leonabdalla]

Hi, i am doing a DM calculation on Vasp. I am studying Bi2Se3 surfaces with Co atoms on it,(which is metalic), and i want to do a good DM calculation with spin orbit.

my poscar is a supercell 2x2x1, with 80 atoms:

i have done optimization of the Encut energie, on a bulk system,
and a optimization of kpoint on the surface (where i use gamma centered, which is recomended in vasp manual for metalic hexagonal cells)

the encut energie optimizaed is the same as in POTCAR (i made the test convergence to be less than 1 mev/atom)

the kpoint for the unit cell was 5x5x1

so in my calculation of supercell i used KPOINTS 3x3x1 centered on gamma

my INCAR is the folowing:

ENCUT = 268
ENAUG = 478
ISPIN = 2
NELM = 100
NELMIN = 4
EDIFF = 1E-5
AMIN= 0.01

EDIFFG = -1E-2
NSW=0
IBRION=-1
ISIF= 0

ISMEAR = 1
SIGMA = 0.01
LREAL=AUTO
ALGO = Normal
LSORBIT = .TRUE.
LMAXMIX = 6

But i doest converge, i even have look on the vasp hand on, and they say to put ICHARG=12 and see if it converge

well it did, then i was playing with converging parameters, but it doesn t converge,
i put ICHARG=2 and AMIX=0.1 BMIX= 0.01, and still no convergence.

on the OSZISCAR i have dE jumping like crazy
i dont know anymore what to do

PS: i cannot put a lot of KPOINT because i may have problems with memory

[support_vasp]

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP