Pressure-induced isostructural phase transition of metal-doped silicon clathrates

TL;DR

This paper presents an atomistic model explaining the pressure-induced isostructural phase transition in metal-doped silicon clathrates, matching experimental observations and exploring effects of doping and substitution.

Contribution

It introduces a novel atomistic model that accurately describes the phase transition and its dependence on doping and atomic substitution in silicon clathrates.

Findings

Model successfully explains the equation of state and transition pressures.

Reproduces changes in Raman spectra during phase transition.

Shows effects of different dopants and substitutions on transition behavior.

Abstract

We propose an atomistic model for the pressure-induced isostructural phase transition of metal-doped silicon clathrates, Ba8Si46 and K8Si46, that has been observed at 14 GPa and 23 GPa, respectively. The model explains successfully the equation of state, transition pressure, change of Raman spectra and dependence on the doped cations as well as the effects of substituting Si(6c) atoms with noble metals.