Half-metallic ferromagnetism with tunable magnetic anisotropy in Fe-doped MoTe2 monolayer: A first-principles study

Abstract

High Curie temperature half-metallic ferromagnetism and tunable magnetic anisotropy are of great importance for spintronic applications. In this work, the electronic and magnetic properties of MoTe₂ monolayer under impact of Fe doping are systematically investigated using first-principles calculations. Pristine MoTe₂ monolayer is nonmagnetic semiconductor two-dimensional (2D) material, having a direct band gap of 1.08 eV. The monolayer is significantly magnetized by substitutional Fe doping, which induces also the magnetic semiconductor nature. In this case, magnetic moment is produced primarily by impurity, where its nearest neighboring Te and Mo atoms also make little contribution that exhibit the antiparallel spin coupling with Fe atom to generate a zero overall magnetic moment. Our calculations demonstrate the half-metallic ferromagnetism in Fe-doped MoTe₂ monolayer with high Curie temperature of 650 K and in-plane magnetic anisotropy (IMA). Further, creating additional single Te vacancy and Se doping are proposed to alter the system magnetic anisotropy. It is found that Curie temperature decreases to 189 and 489 K, respectively. Nevertheless, single Te vacancy induces the switching from in-plane to perpendicular magnetic anisotropy (IMA-to-PMA switching). Meanwhile Se doping maintains the IMA in Fe-doped MoTe₂ monolayer, however the magnetic anisotropy is enhanced as confirmed by the increase of magnetic anisotropy energy. Both routes preserve the half-metallicity with perfect spin polarization. In addition, formation energy analysis, ab initio molecular dynamics (AIMD) simulations and the computed cohesive energy suggest good stability of the doped/defected MoTe₂ monolayers, suggesting their feasible realization in experiments. Our findings recommend promising 2D candidates for spintronic applications with tunable magnetic anisotropy formed through the structural modification of MoTe₂ monolayer, specifically towards magnetic field sensing (with IMA) and magnetoresistive random access memories (with PMA).