Pressure-driven phase transitions in correlated systems

TL;DR

This paper demonstrates that first principles Car-Parrinello molecular dynamics effectively models pressure-driven phase transitions in correlated systems, aligning well with experimental observations.

Contribution

It introduces a computational approach to understand microscopic mechanisms behind pressure-induced phase transitions in Mott insulators and correlated metals.

Findings

Pressure induces insulator to metal transition in TiOCl.

Pressure causes structural and magnetic transitions in $A$Fe$_2$As$_2$.

Predictions match well with experimental data.

Abstract

Motivated by recent experimental measurements on pressure-driven phase transitions in Mott-insulators as well as the new iron pnictide superconductors, we show that first principles Car-Parrinello molecular dynamics calculations are a powerful method to describe the microscopic origin of such transitions. We present results for (i) the pressure-induced insulator to metal phase transition in the prototypical Mott insulator TiOCl as well as (ii) the pressure-induced structural and magnetic phase transitions in the family of correlated metals $A$Fe$_2$As$_2$ ($A$=Ca,Sr,Ba). Comparison of our predictions with existing experimental results yields very good agreement.