Electronic property and bonding configuration at the TiN(111)/VN(111) interface

Multilayered TiN(111)/VN(111) coatings find many technological applications where the behaviors of their inside interfaces are known or suspected to influence functionalities in such an engineering surface system. Here, we demonstrate, by first-principles calculations on energetics and electronic structures of a total of 36 candidate interfaces, that the preferred geometries (i.e., that having the largest adhesion energy) are those that retain the interface structures as in either of the nitride bulks both atomically and electronically. Using several analytic methods, we have thoroughly characterized electronic states and determined that the interfacial bondings are mainly ionic, yet maintain a small amount of covalent character. The theoretical calculations presented provide insight into the complex electronic properties of the functional TiN/VN interface that could be difficult to obtain by experiment alone but which are practically important for further understanding and improvement of such a multilayered coating at the atomic scale.