Electronic structure of M₂AlC(0001) surfaces (M = Ti,V,Cr)

We have studied the correlation between the valence electron configuration and the electronic structure of M₂AlC(0001) surfaces (M ≤ Ti, V, Cr) using ab initio calculations. Based on our surface energy data, we find that the Al termination is the most stable configuration. As the M valence electron population is increased, the surface energy increases. This can be understood by analysing the valence electron concentration induced changes of the electronic structure. Antibonding states are present as Ti is substituted by Cr in M ₂AlC(0001). These results are of relevance for vapour phase condensation as well as oxidation.