Tunable magneto-optical effect, anomalous Hall effect, and anomalous Nernst effect in the two-dimensional room-temperature ferromagnet 1T−CrTe2

Abstract

Utilizing 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 the recently discovered two-dimensional room-temperature ferromagnet $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$. 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 $2\ensuremath{\pi}/3$ when the spin rotates within the atomic plane, and they are forbidden if a mirror plane perpendicular to the spin direction exists. By reorienting the spin from the 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 of multilayer $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$ and predict antiferromagnetism and ferromagnetism for bilayer and trilayer $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$, respectively. The MOE, AHE, and ANE are prohibited in antiferromagnetic bilayer $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$ due to the existence of the space-time inversion symmetry, whereas all of them are activated in ferromagnetic trilayer $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$ and are significantly enhanced compared to those of monolayer $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$. Our results show that the magneto-optical and anomalous transports proprieties of $1T\text{\ensuremath{-}}{\mathrm{CrTe}}_{2}$ can be effectively modulated by altering spin direction and layer number.