Two‐dimensional (2D) Janus transition metal dichalcogenide (TMDC) materials are significant for manipulating electron spin, crucial for spintronic and valleytronic applications, because of their distinctive lattice structures and emergent physical properties. These systems host structural asymmetry due to the breaking of both in‐plane inversion and out‐of‐plane mirror symmetry operations, offering a plethora of emerging phenomena. In this study, we employ first‐principles calculations to explore 2D Janus alloys Mo x W 1− x STe for x = 0, 0.25, 0.5, 0.75, and 1. Here, for the first time, we unveil how alloying two materials with distinct structural, electronic, and spin–orbit coupling‐driven relativistic features can tune the Zeeman‐type spin‐splitting between two valleys or energy extrema in the reciprocal space, and the Rashba effect in Janus TMDCs. Alloy substitution introduces an extra degree of freedom, which modulates spin‐valley coupling, useful for information processing and memory storage. Our results find that the W‐rich TMDC alloys exhibit larger valley splitting at K / K ’ valleys and a significant Rashba parameter around the Γ point due to stronger SOC compared to the Mo‐rich systems. Since alloy substitution further lowers the symmetry elements, this enhances the magnitude of the induced dipole moment. We demonstrate how to tune various physical phenomena by controlling the chemical composition of 2D TMDC alloys. Our research proposes that janusization, combined with alloying, can alter the characteristics of atomically thin TMDCs, making these systems potential candidates for next‐generation technologies.
Dar et al. (Thu,) studied this question.