Speaker
Description
The H-phase of vanadium ditelluride (H-VTe$_2$) recently gained interest in spintronics due to its room-temperature ferromagnetism and tunable electronic band gap [1]. The stability of its ferromagnetic ordering in the monolayer structure can be attributed to its large magnetic anisotropy energy (MAE), favoring in-plane magnetization. Modulating the magnetic anisotropy is crucial in improving low-dimensional spintronic devices; one of the effective methods to achieve this is through electrostatic doping [2]. Yet, the underlying mechanism driving the changes in MAE upon doping is still unclear. We performed a density functional theory study to determine the effect of electrostatic doping on the electronic and magnetic properties of H-VTe$_2$ monolayer. Our calculations revealed that hole doping increases the magnitude of MAE in the order of millielectronvolts, switching the magnetic anisotropy to easy out-of-plane magnetization even for small doping concentrations. We found that the interplay of orbital hybridization, exchange splitting, and crystal field splitting from the trigonal prismatic coordination pushes a two-fold degenerate $d_{xz}$/$d_{yz}$ state to the valence band edge at $\Gamma$. The energy splitting of this doublet due to SOC is crucial in lowering the fully relativistic total energy of the system upon hole doping when the magnetization axis is perpendicular to the surface. Aside from the switching of MAE, we found that hole doping induces a semiconductor to half-metal transition and enhances the magnetic moment, which makes H-VTe$_2$ a promising material for spintronics application. The proposed mechanism for the influence of electrostatic doping on MAE can also apply to other systems where spin-orbit coupling affects states near the Fermi level.
References
[1] M. Jafari, W. Rudziński, J. Barnaś, and A. Dyrdał, Electronic and magnetic properties of 2D vanadium-based transition metal dichalcogenides, Sci Rep 13, (2023).
[2] R. Han, X. Xue, and Y. Yan, Hole-Doping-Induced Perpendicular Magnetic Anisotropy and High Curie Temperature in a CrSX (X = Cl, Br, I) Semiconductor Monolayer, Nanomaterials 13, 3105 (2023).
