Ferroelectric and negative piezoelectric properties in oxyhydroxide monolayers γ -XOOH (X = Al, Ga, and In)

Abstract

Two-dimensional (2D) multiferroic materials with coexisting ferroelasticity (FA) and ferroelectricity (FE) have potential applications in high-density data storage and sonar detectors. Here, based on first-principles calculations, we predict a series of stable 2D FA-FE multiferroic structures, namely, γ-XOOH (X = Al, Ga, and In) monolayers. By analyzing the lattice symmetry and orientation distribution of hydroxyls, we find that XOOH monolayers possess both in-plane ferroelastic and ferroelectric polarization, as well as antiferroelectric ordering caused by the anti-parallel alignment of hydroxyls. Interestingly, the perpendicular reorientation of in-plane FE polarization accompanies 90° ferroelastic switching. Moreover, they show an unusual negative transverse piezoelectric effect originated from the clamped-ion term. The multiferroic properties of the XOOH monolayers provide an excellent platform to study electroelastic effects.

Room-Temperature Ferroelectricity, Ferromagnetism, and Anomalous Hall Effect in Half-Metallic Monolayer CrTe

“…40 Oxyhydroxide monolayers γ-XOOH (X = Al, Ga, and In) have low exfoliation energy and show spontaneous ferroelasticity, ferroelectric with negative piezo response, with promising applications in future nonvolatile memory devices. 41 Se; Y = Cl, Br, I) are shown to have room-temperature ferromagnetism with sliding ferroelectricity 42 and multiferroicity with large in-plane piezoelectricity, 43 respectively.…”

“…Bulk CdTe exfoliated along the [110] facet shows a stable monolayer with improved optoelectronic properties . Oxyhydroxide monolayers γ-XOOH (X = Al, Ga, and In) have low exfoliation energy and show spontaneous ferroelasticity, ferroelectric with negative piezo response, with promising applications in future nonvolatile memory devices . Several 2D chalcogenides such as 1T′α-VXY (X = S, Se, Te; Y = Cl, Br, I) and AlXY (X = S, Se; Y = Cl, Br, I) are shown to have room-temperature ferromagnetism with sliding ferroelectricity and multiferroicity with large in-plane piezoelectricity, respectively.…”