Tunable magneto-optical effect, anomalous Hall effect and anomalous Nernst effect in two-dimensional room-temperature ferromagnet $1T$-CrTe$_2$

TL;DR

This study uses first-principles calculations to explore how spin orientation and layer number affect magneto-optical, anomalous Hall, and Nernst effects in 2D ferromagnetic $1T$-CrTe$_2$, revealing tunable properties at room temperature.

Contribution

It provides a comprehensive analysis of spin-dependent effects and layer-dependent magnetic properties in $1T$-CrTe$_2$, highlighting their tunability for potential applications.

Findings

MOE, AHE, and ANE depend on spin orientation within the plane.

Enhancement of effects when reorienting spin out-of-plane.

Layer number influences magnetic order and related effects.

Abstract

Utilizing the first-principles density functional theory calculations together with group theory analyses, we systematically investigate the spin order-dependent magneto-optical effect (MOE), anomalous Hall effect (AHE), and anomalous Nernst effect (ANE) in a recently discovered two-dimensional room-temperature ferromagnet $1T$-CrTe$_2$. We find that the spin prefers an in-plane direction by the magnetocrystalline anisotropy energy calculations. The MOE, AHE, and ANE display a period of $2\pi/3$ when the spin rotates within the atomic plane, and they are forbidden if there exists a mirror plane perpendicular to the spin direction. By reorienting the spin from in-plane to out-of-plane direction, the MOE, AHE, and ANE are enhanced by around one order of magnitude. Moreover, we establish the layer-dependent magnetic properties for multilayer $1T$-CrTe$_2$ and predict antiferromagnetism and ferromagnetism for bilayer and trilayer $1T$-CrTe$_2$, respectively. The MOE, AHE, and ANE are prohibited in antiferromagnetic bilayer $1T$-CrTe$_2$ due to the existence of the spacetime inversion symmetry, whereas all of them are activated in ferromagnetic trilayer $1T$-CrTe$_2$ and the MOE is significantly enhanced compared to monolayer $1T$-CrTe$_2$. Our results show that the magneto-optical and anomalous transports proprieties of $1T$-CrTe$_2$ can be effectively modulated by altering spin direction and layer number.