Multifunctional Altermagnet with Large Out-of-Plane Piezoelectric Response in Janus V$_{2}$AsBrO Monolayer

TL;DR

This paper introduces a novel Janus V₂AsBrO monolayer that exhibits altermagnetism, out-of-plane piezoelectricity, and strain-tunable valley polarization, offering potential for multifunctional 2D nanoelectronic devices.

Contribution

It proposes a new altermagnetic semiconductor with high Curie temperature, strain-tunable properties, and significant piezoelectric response, expanding the scope of 2D multifunctional materials.

Findings

Exhibits out-of-plane piezoelectric coefficient of 2.19 pm/V.

Displays strain-tunable piezovalley effect and valley polarization.

Generates net magnetization via piezomagnetic effect under strain.

Abstract

Altermagnetism has emerged as a third fundamental category of collinear magnetism, characterized by spin-splitting in symmetry-compensated collinear antiferromagnets, opening new frontiers in spintronics and condensed matter physics. Here, based on first-principles calculations, we propose a novel altermagnetic semiconductor, the asymmetric Janus V$_2$AsBrO monolayer, which exhibits a magnetic easy axis favoring the out-of-plane direction and a N\'{e}el temperature ($T_N$) exceeding room temperature. The system exhibits a strain-tunable piezovalley effect, generating valley polarization under uniaxial strain. Notably, hole doping under uniaxial strain generates a net magnetization ($M$) through a piezomagnetic mechanism. Additionally, the broken inversion symmetry endows the monolayer with a substantial out-of-plane piezoelectric coefficient $d_{31}$ (2.19 pm/V), presenting broad prospects for the development and design of novel piezoelectric devices. Our findings provide a promising candidate material for the advancement of 2D multifunctional devices in nanoelectronics, spintronics, valleytronics, and piezoelectrics.