Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5368045 | Applied Surface Science | 2011 | 5 Pages |
The structures of the CoAl(1Â 1Â 1) surface are studied by first principles calculations. Our calculations show that the surface layer is always occupied by pure Al for all concentrations studied here, which indicates the dominant role of the Al segregation tendency. This is different from the CoAl(0Â 0Â 1) surface, where a number of Co anti-sites are found on the top most layer. The calculated surface phase diagram of ground states shows that there are three stable structures. The diffusion barriers of the metastable structure evolving to the stable structure are also calculated. The high diffusion barrier can explain the appearance of metastable structures at low temperature in experiment.
Research highlightsⶠAl segregation tendency plays dominant role on the CoAl(1 1 1) surface. ⶠThere are three stable states in the CoAl(1 1 1) surface phase diagram. ⶠThe barriers from the initial surface structure to the stable structure are large.