Auxetic and multiferroic MP5 (M = Al, Ga): a novel 2D material with negative Possion's ratio and high anisotropic carrier mobility.

Abstract

In the field of materials science, the development of multifunctional 2D materials has been a long-standing research objective. In this study, we employ first-principles calculations to predict a novel 2D material named MP5 (M = Al, Ga), which exhibits ferroelasticity, ferroelectricity, negative Poisson's ratio, and high anisotropic carrier mobility. Our investigation reveals that a single layer of MP5 displays multiferroic behavior, wherein ferroelasticity and ferroelectricity are coupled. The remarkable structural anisotropy of MP5 enables easy switching between ferroelastic and ferroelectric states, rendering it suitable for nonvolatile memory applications. Simultaneously, monolayer AlP5 (GaP5) demonstrates a negative Poisson's ratio of -0.074 (-0.058) and a carrier mobility of up to 91 720 cm2 V-1 S-1 (99 690 cm2 V-1 S-1). These exceptional properties position monolayer MP5 as a highly versatile and promising 2D material for implementation in nanomechanical and microelectromechanical devices.