High-pressure cupric oxide: a room-temperature multiferroic

TL;DR

This study predicts that applying high pressure to cupric oxide (CuO) can stabilize its multiferroic phase at room temperature, enabling potential applications in multi-state memory devices with electrical writing and magnetic read-out.

Contribution

The paper demonstrates through computational methods that pressure induces a stable multiferroic phase in CuO at room temperature, overcoming previous temperature limitations.

Findings

High pressure stabilizes multiferroic phase of CuO above 300 K.

Pressure range of 20-40 GPa induces multiferroicity at room temperature.

CuO exhibits large ferroelectric polarization under high pressure.

Abstract

Multiferroic materials, in which ferroelectric and magnetic ordering coexist, are of fundamental interest for the development of multi-state memory devices that allow for electrical writing and non-destructive magnetic read-out operation. The great challenge is to create multiferroic materials that operate at room-temperature and have a large ferroelectric polarization P. Cupric oxide, CuO, is promising because of its large P ~ 10^{2} {\mu}C.m^{-2}, but is unfortunately only multiferroic in a temperature range of 20 K, from 210 to 230 K. Here, using a combination of density functional theory and Monte Carlo calculations, we establish that pressure-driven phase competition induces a giant stabilization of the multiferroic phase of CuO, which at 20-40 GPa becomes stable in a domain larger than 300 K, from 0 to T > 300 K. Thus, under high-pressure, CuO is predicted to be a room-temperature multiferroic with large polarization.