The effect of carrier concentration on the electronic structure and magnetothermal properties of a two-dimensional VTe2 monolayer with a high Curie temperature†

Abstract

Two-dimensional (2D) magnetic transition metal dichalcogenides have unique electronic properties, ferromagnetism, and tunable properties in low-dimensional systems. In this paper, the structural, electronic, and magnetic properties of the VTe₂ monolayer under different carrier concentrations were investigated using first-principles calculations and Monte Carlo (MC) simulations. It is found that by introducing a suitable number of electrons, the VTe₂ monolayer can undergo a transition from a semiconductor to a half-metal state, with 100% spin polarization. The magnetocrystalline anisotropy energy is up to 1855.62 μeV in the z-axis direction, which is conducive to maintaining ferromagnetic order above room temperature. In particular, the easy magnetic axis can undergo an in-plane to out-of-plane transition when doped with a small number of holes. In addition, doping can sensitively enhance or weaken the ferromagnetic exchange coupling strength. The magnetothermal results show that the Curie temperature of the VTe₂ monolayer is 547 K in the absence of a size effect, and can be further increased to 574 K when hole doping reaches 1.825 × 10¹³ cm⁻² (0.02 holes per atom). Increasing magnetocrystalline anisotropy and magnetic field can also make the Curie temperature larger. Our results suggest the potential applications of VTe₂ in spintronics and provide a deeper understanding of the modulation mechanism.