Non-constant vacuum potential with dipole corrections enabled
Hi,
I have been modelling a 4 layer thick Ag slab at the z-edge of a (4x4) supercell. When I adsorb an oxygen atom to one side of the slab, this creates a dipole which I am trying to correct for. However, when I turn on dipole corrections using the relevant tags in the INCAR, the LOCPOT file remains unchanged relative to without the dipole correction tags and the potential in the vacuum region remains sloped, not constant as it should be. I have a 15 angstrom vacuum above the adsorbed atom in the z-direction (and have tried with larger giving the same result). I'm wondering if there is a conflicting tag in my INCAR file that could be messing with this correction, as I am not seeing a 'step' in the potential in the vacuum region as I have seen is expected. In the OUTCAR file, VASP is reading and turning on the dipole correction but I do not see this result in the LOCPOT. I will attach my INCAR below, as well as an image of my cell and plot of the planar averaged electrostatic potential obtained with these INCAR settings. Any help you could provide would be much appreciated.
ISPIN = 2
GGA = BF
LUSE_VDW = .TRUE.
Zab_VDW = -1.8867
LBEEFENS = .TRUE.
ICHARG = 1
ENCUT = 500
EDIFF = 1.00e-06
EDIFFG = -0.01
LREAL = Auto
NELM = 120
NSW = 400
IBRION = 2
POTIM = 0.1
KPAR = 5
NCORE = 6
ISMEAR = 1
SIGMA = 0.2
ISIF = 2
LVHAR = .True.
LDIPOL = .True.
IDIPOL = 3
LORBIT = 11
LASPH = .TRUE.