First-principles study of MgB2 film on the MgO(111) polar surface

First-principles density functional calculations are applied to study the growth behavior of MgB2(0001) film on MgO(111) polar surface. The surface energy calculations show that under Mg-rich conditions, Mg-terminated MgO(111) is favored, while the O-terminated is more favorable under O-rich conditions. By exploring three typical models, we calculate the interface energy that is examined as a function of the chemical potentials of Mg. It is found that the most stable structure is preferred to be Mg-terminated MgO(111)-(1×11×1)-BMgB-structure, where B atom is bonded to Mg atom at a hollow (top) site in interface.