Electronic correlation assisted ferroelectric metallic state in LiOsO$_3$

TL;DR

This study combines experimental infrared spectroscopy with advanced theoretical calculations to reveal that LiOsO$_3$ is a strongly correlated bad metal near a Mott transition, supporting its classification as a ferroelectric metal.

Contribution

It provides a comprehensive analysis of the electronic correlations in LiOsO$_3$, demonstrating the role of electron-electron interactions in its ferroelectric metallic state.

Findings

LiOsO$_3$ is a very bad metal with low quasiparticle weight.

Strong electron-electron correlations dominate its optical conductivity.

LiOsO$_3$ is close to a Mott-Hubbard localization transition.

Abstract

LiOsO$_3$ has been recently identified as the first unambiguous "ferroelectric metal", experimentally realizing a prediction from 1965 by Anderson and Blount. In this work, we investigate the metallic state in LiOsO$_3$ by means of infrared spectroscopy supplemented by Density Functional Theory and Dynamical Mean Field Theory calculations. Our measurements and theoretical calculations clearly show that LiOsO$_3$ is a very bad metal with a small quasiparticle weight, close to a Mott-Hubbard localization transition. The agreement between experiments and theory allows us to ascribe all the relevant features in the optical conductivity to strong electron-electron correlations within the $t_{2g}$ manifold of the osmium atoms.