Structural properties and bonding characteristic of interfaces between VN and VC from density functional calculations

Based on the density functional theory, the interfacial structures, the interfacial ideal work of adhesion and the interfacial bonding of VN(100)/VC(100), VN(110)/VC(110), and VN(111)/VC(111) interfaces were investigated. The results reveal that the (100) surface is more stable than (110) for both VN and VC. The surface energy of VC (111) or VN (111), as nonstoichiometric surface, is not constant that varies with the different chemical potentials of V (or C/N). The V-terminated structure is more stable than the C-terminated structure for VC (111) surface. For VN (111) surface, the V-terminated structure is more stable than the N-terminated one in the N-rich field, in contrast the N-terminated structure is more stable than the V-terminated one in the V-rich field. The adhesion energy of the most stable (111) interface is larger than that of (100) interface and (110) interface. Interfacial termination structure plays an important role in the interface stability, and the interface with the V C or V N bonds forming is more stable than other interfaces with V V and C N bonds. The stacking sequence also influences the interfacial stability, and those building types keeping the continuity of VN (VC) structure have high stability. These theoretical analyses will provide some suggestions on the orientation control during the multilayered film preparation.