Prediction of interesting ferromagnetism in Janus semiconducting Cr$_2$AsP monolayer

TL;DR

This study predicts that Janus Cr$_2$AsP monolayer exhibits tunable ferromagnetism and half-metallicity under doping and strain, making it promising for spintronic applications.

Contribution

First-principles calculations reveal the intrinsic ferromagnetic semiconducting nature and strain/doping-induced half-metallicity of Cr$_2$AsP monolayer, advancing 2D spintronic material design.

Findings

Cr$_2$AsP$ is an intrinsic ferromagnetic semiconductor.

Se doping induces transition to half-metallicity.

Biaxial strain causes magnetic phase transitions.

Abstract

Two-dimensional (2D) half-metallic materials that have sparked intense interest in advanced spintronic applications are essential to the developing next-generation nanospintronic devices. Here we have adopted a first-principles calculation method to predict the magnetic properties of intrinsic, Se-doped, and biaxial strain tuning Cr$_2$AsP monolayer. The Janus Cr$_2$AsP monolayer is proved to be an intrinsic ferromagnetic (FM) semiconductor with a exchange splitting bandgap of 0.15 eV at the PBE+U level. Concentration-dependent Se doping such as Cr$_2$As$_{1-x}$Se$_x$P (x = 0.25, 0.50, 0.75) can regulate Cr$_2$AsP from FM semiconductor to FM half-metallicity. Specifically, the spin-up channel crosses the Fermi level, while the spin-down channel has a bandgap. More interestingly, the wide half-metallic bandgaps and spin bandgaps make them have important implications for the preparation of spintronic devices. At last, we also explore the effect of biaxial strain from -14% to 10% on the magnetism of the Cr$_2$AsP monolayer. There appears a transition from FM to antiferromagnetic (AFM) at a compressive strain of -10.7%, originating from the competition between the indirect FM superexchange interaction and the direct AFM interaction between the nearest-neighbor Cr atoms. Additionally, when the compressive strain to -2% or the tensile strain to 6%, the semiconducting Cr$_2$AsP becomes a half-metallic material. These charming properties render the Janus Cr$_2$AsP monolayer with great potential for applications in spintronic devices.