Large magnetic anisotropy and strain induced enhancement of magnetic anisotropy in monolayer TaTe₂

Abstract

Monolayer TaTe₂ holds great potential for the realization of large magnetocrystalline anisotropy due to strong spin-orbit coupling (SOC) interactions of Ta. Here, we systematically investigate the electronic structure, magnetism and magnetocrystalline anisotropy of monolayer TaTe₂ under different strains by means of first-principles calculations. The results show that monolayer TaTe₂ is a ferromagnetic metal and exhibits a large in-plane magnetic anisotropy energy (MAE) of -11.38 meV per TaTe₂. It is worth noting that the magnetic moment, magnetic coupling and magnetic anisotropy of monolayer TaTe₂ are significantly enhanced by strain. In particular, when tensile strain increases from 0% to 8%, the MAE of monolayer TaTe₂ greatly increases from -11.38 to -15.14 meV per TaTe₂. By analyzing the density of states and the contribution to magnetocrystalline anisotropy (MCA) from the SOC interaction between two d orbitals of Ta atoms based on second-order perturbation theory, it is concluded that a large MAE of monolayer TaTe₂ is mainly contributed by the SOC interaction between opposite spin d_xy and d_x²-y² orbitals of Ta atoms and the significant increase of the negative contribution to MCA from the SOC interaction between opposite spin d_xy and d_x²-y² orbitals under strain is the reason why the MAE of monolayer TaTe₂ is significantly enhanced by strain. Our results indicate that monolayer TaTe₂ is a promising candidate suitable for applications in magnetic storage devices.