# Lattice dynamics and phase stability of rhombohedral antimony under high pressure

## TL;DR

This study investigates the lattice dynamics and phase stability of rhombohedral antimony under high pressure using experimental scattering techniques and theoretical models, revealing phonon behavior and structural transition mechanisms.

## Contribution

It combines diffuse scattering, inelastic x-ray scattering, and theoretical approaches to analyze phonon behavior and phase transitions in antimony under high pressure, highlighting vibrational roles in structural changes.

## Key findings

- Phonon dispersion shows complex behavior near phase transition.
- Softening of phonon branches indicates impending structural transitions.
- Vibrations play a key role in driving the SbI-SbIV phase change.

## Abstract

The high pressure lattice dynamics of rhombohedral antimony have been studied by a combination of diffuse scattering and inelastic x-ray scattering. The evolution of the phonon behavior as function of pressure was analyzed by means of two theoretical approaches: density functional perturbation theory and symmetry-based phenomenological phase transition analysis. This paper focuses on the first structural phase transition, SbI-SbIV, and the role of vibrations in leading the transition. The phonon dispersion exhibits complex behaviour as one approaches the structural transition, with the branches, corresponding to the two transitions happening at high pressure in the Va elements (A7-to-BCC and A7-to-PC) both showing softening.