Atomic and electronic structure of the TiN/MgO interface from first principles

Abstract

The atomic structure, adhesion energy, electronic states, and interfacial bonding nature of the TiN(001)/MgO(001) and TiN(110)/MgO(110) interfaces are systematically investigated by first principles calculations. Two possible models for TiN(001)/MgO(001) interfaces with an orientation relationship of [010](001)TiN//[010](001)MgO and four models for TiN(110)/MgO(110) interfaces with an orientation relationship of [001](110)TiN//[001](110)MgO were considered. Through the calculations of adhesion energies of all the candidate interfaces, it was found that the interface with cation–anion bonding configurations (namely, Ti–O and Mg–N) is energetically favorable for TiN(001)/MgO(001) interfaces and the interface with N(Ti) atoms located above bridge sites between Mg(O) atoms of TiN(110)/MgO(110) interfaces shows the largest adhesion energy; in addition, the orientation relationship has a significant impact on the stability of the interface. By applying some analytical methods, we characterized the electronic structure and found that the interfacial bonding is mainly ionic with a small degree of covalence.