Ab initio study of high-pressure structural properties of the LuVO₄ and ScVO₄ zircon-type orthovanadates

Abstract

We use ab initio theoretical methods to study the relative stability under pressure of the zircon, scheelite and fergusonite structures in the LuVO₄ and ScVO₄ orthovanadates. In LuVO₄, our study confirms the zircon→scheelite→fergusonite sequence of stable phases proposed in previous experimental works. In ScVO₄, we find a zircon-to-scheelite phase transition in agreement with experiments. At higher pressures, our calculations show that the scheelite phase becomes unstable with respect to the fergusonite phase, although no second phase transition has been observed in experiments.

Keywords:

• phase transition
• pressure
• ab initio calculations
• vanadates

Acknowledgements

We acknowledge the financial support of the Spanish MCYT under grants MAT2007-65990-C03-03 and CSD2007-00045, and the supercomputer time provided by the Red Española de Supercomputación.