A nine-fold coordinated vanadium by oxygen in V2O3 from first-principles calculations
Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education & School of Earth and Space Sciences, Peking University, Beijing 100871, P.R. China
Received: 25 April 2012
Received in final form: 11 June 2012
Published online: 6 August 2012
Crystal structural stability of V2O3 under high pressure has been investigated by first-principles calculations. Our results demonstrate that the phase-transition sequence of V2O3 is from corundum structure to Gd2S3-type structure at 30 GPa, then to the Th2S3-type structure at 52 GPa, finally to the Os2Al3-type structure at 257 GPa. The latest Os2Al3-type structure with nine-fold coordinated cation is denser than previous reported models in sesquioxides, which is vibrationally stable at least at 329 GPa supported by its phonon spectrum. According to the contributions of different components to enthalpy, the Gd2S3-to-Th2S3 and Th2S3-to-Os2Al3 transitions are mainly caused by the volume contraction.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2012