Oxygen interstitial diffusion

lexa · Post by **lexa** » Thu Mar 24, 2011 8:17 am

Hi all,

I am trying to calculate the diffusion path of Oxygen in Silicon. The literature says that the Oxygen sits in the mid of a Si-Si bond. Before running the NEB i fully relax my system with an Oxygen atom nearly sitting at the mid of a Si-Si bond. I am not able to reproduce the the Si-O-Si configuration as reported, and my NEBs for the diffusion from one interstitial position to the other gives very high barriers.

My INCAR for the relaxations is bellow:

SYSTEM = O_Si
LWAVE = .F
LCHARG = .F
LPLANE = .T
ENCUT = 400

PREC = Accurate
EDIFF = 1E-05
EDIFFG = -0.001

NELM = 80 max number of electronic steps
NELMIN = 6

NSW = 200
IBRION = 3
ISIF = 3
POTIM = 0.1

ISMEAR = 0
SIGMA = 0.05
IALGO = 48
LREAL = AUTO

I'll appreciate your help,
many thanks,
Alexandra