Anharmonicity-induced isostructural phase transition of Zirconium under pressure

TL;DR

This study combines experimental x-ray diffraction and theoretical calculations to reveal an anharmonicity-driven isostructural phase transition in zirconium under high pressure, emphasizing the role of anharmonic effects.

Contribution

It provides the first clear experimental and theoretical evidence of an anharmonicity-induced isostructural phase transition in zirconium at high pressure.

Findings

Identified a first-order bcc-to-bcc phase transition near 58 GPa.

Supported experimental results with quantum molecular dynamics calculations.

Highlighted the potential ubiquity of anharmonicity-driven transitions in the periodic table.

Abstract

We have performed a detailed x-ray diffraction structural study of Zr under pressure and unambiguously identify the existence of a first-order isostructural bcc-to-bcc phase transition near 58 GPa. First-principles quantum molecular dynamics lattice dynamics calculations support the existence of this phase transition, in excellent agreement with experimental results, triggered by anharmonic effects. Our results highlight the potential ubiquity of anharmonically driven isostructural transitions within the periodic table under pressure and calls for follow-up experimental and theoretical studies.