Phase stability, chemical bonding and mechanical properties of titanium nitrides: A first-principles study

Shuyin Yu, Qingfeng Zeng, Artem R. Oganov, Gilles Frapper, Litong Zhang

Research output: Contribution to journalArticlepeer-review

87 Citations (Scopus)

Abstract

We have performed first-principles evolutionary searches for stable Ti-N compounds and have found, in addition to the well-known rock-salt TiN, new ground states Ti3N2, Ti4N3, Ti6N5 at atmospheric pressure, and Ti2N and TiN2 at higher pressures. The latter nitrogen-rich structure contains encapsulated N2 dumbbells with a N-N distance of 1.348 Å at 60 GPa. TiN2 is predicted to be mechanically stable and quenchable. Our calculations on the mechanical properties (bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and hardness) are in excellent agreement with the available experimental data. Further analyses of the electronic density of states, crystal orbital Hamilton population and the electron localization function reveal that the hardness is enhanced by strengthening directional covalent bonds and disappearance of Ti-Ti metallic bonding. This journal is

Original languageEnglish
Pages (from-to)11763-11769
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number17
DOIs
Publication statusPublished - 7 May 2015
Externally publishedYes

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