Metallic ferroelectricity induced by anisotropic unscreened coulomb interaction in LiOsO3

TL;DR

This paper investigates the unique ferroelectric behavior of LiOsO3, revealing that anisotropic unscreened Coulomb interactions enable ferroelectric order in a metallic system.

Contribution

It demonstrates that anisotropic unscreened Coulomb interactions induce ferroelectricity in LiOsO3, clarifying the transition mechanism and the role of anisotropic screening.

Findings

Ferroelectric transition is order-disorder like.

Electric screening is highly anisotropic.

Unscreened dipole interactions enable ferroelectric order in a metal.

Abstract

As the first well-documented example of the ferroelectric metal, LiOsO3 has received extensive research attention recently. Using density-functional calculations, we perform a systematic study for LiOsO3. We address the controversy about the depth of the double well in the potential surface, and propose that the ferroelectric transition is order-disorder like. Moreover, we unambiguously demonstrate that the electric screening in this compound is highly anisotropic, and there is still unscreened dipole-dipole interaction in one special direction which results in the long range ferroelectric order despite the metallic nature of LiOsO3.