Stability of rhombohedral phases in vanadium at high-pressure and high-temperature: first-principles investigations.

ABSTRACT: The pressure-induced transition of vanadium from BCC to rhombohedral structures is unique and intriguing among transition metals. In this work, the stability of these phases is revisited by using density functional theory. At finite temperatures, a novel transition of rhombohedral phases back to BCC phase induced by thermal electrons is discovered. This reentrant transition is found not driven by phonons, instead it is the electronic entropy that stabilizes the latter phase, which is totally out of expectation. Parallel to this transition, we find a peculiar and strong increase of the shear modulus C44 with increasing temperature. It is counter-intuitive in the sense that it suggests an unusual harding mechanism of vanadium by temperature. With these stability analyses, the high-pressure a

SUBMITTER: Wang YX 

PROVIDER: S-EPMC5007533 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature