Enhanced Magnetic Anisotropy in Strained V-Doped Janus WSSe Nanosheets: A First-Principles Study on Asymmetric d-p-d Hybridization with Implications for Spintronic Applications

초록

Despite glimpses of promise, achieving long-range spin order at room temperature in magnetically doped two-dimensional (2D) semiconductors remains a major challenge. Two key strategies to enhance the Curie temperature (T-C) in doped transition metal dichalcogenides (TMDs) are (1) optimizing hybridization for strong exchange coupling (J) and (2) enhancing local anisotropy for high magnetic anisotropy energy (MAE). In this study, we employ first-principles calculations and Monte Carlo simulations to investigate the electronic and magnetic properties of V-doped WS2, WSe2, and WSSe monolayers, with a focus on the orbital hybridization and strain tunability of WSSe. Our results reveal that WSSe inherits favorable properties from both base materials, WS2 and WSe2, making it a promising diluted magnetic semiconductor (DMS). While WSSe exhibits a slightly reduced dx(2)-y(2)-p(x)/p(y)-dx(2)-y(2) hybridization compared to WSe2, it retains a substantial planar orbital overlap, which can be further enhanced under biaxial compressive strain. From WS2, it inherits a significant d(z)2 -p(z)(2) hybridization, which causes an increased MAE under compressive strain. Hence, this anisotropy in d-p-d hybridization can be a unique knob for controlling the magnetic properties of magnetically doped WSSe. Additionally, site- and orbital-resolved calculations confirm that MAE is primarily governed by neighboring W atoms, with the <dxy|Lz|dx(2)- y(2)> interaction playing a dominant role. The unique combination of asymmetric spin localization, exchange interactions, and strain-enhanced MAE establishes WSSe as a promising material for spintronic applications, offering a pathway toward next-generation magnetic TMD-based devices.

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