title: Role of N defects on thermally induced atomic-scale structural changes in transition-metal nitrides.
abstract: Transition-metal nitrides (TMN) have exceptional stability, which underlies their use in various applications. Here, we study the role of N point defects on the stability of prototype TMNs using first-principles calculations. We find that distinct regimes for TMN changes relate to specific atomic-scale mechanisms, namely, diffusion of N interstitials (I(N)), of I(N) pairs, and of N vacancies. The activation of these processes occurs sequentially as the temperature is raised in a range of several hundreds of degrees, accounting for observed TMN changes under widely different conditions.
authors.affiliation: Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece.
authors.forename: L
authors.initials: L
authors.lastname: Tsetseris
authors.forename: N
authors.initials: N
authors.lastname: Kalfagiannis
authors.forename: S
authors.initials: S
authors.lastname: Logothetidis
authors.forename: S T
authors.initials: ST
authors.lastname: Pantelides