Modulation of Spin-Orbit Coupling, Spin Textures, and Rashba-Edelstein Response in Chiral Tellurium: A First-Principles Study

Abstract: Chiral semiconductors such as elemental tellurium (Te) exhibit unconventional spin textures and large charge-to-spin conversion efficiencies, yet the influence of introducing elements on these properties remains underexplored. Here, we address this gap by investigating how substituting Te with lighter (S, Se) or heavier (Sb) elements systematically modifies the spin-orbit-driven phenomena in chiral Te, including the band structure, spin Berry curvature, and Rashba-Edelstein response. The objective is to determine whether elemental substitution strategies can be leveraged to optimize collinear spin textures, enhance spin accumulation, and possibly extend spin lifetimes all crucial aspects for magnet-free spintronics. Using density functional theory calculations implemented in Quantum ESPRESSO, combined with tight-binding interpolation in PAOFLOW, we map out the element-dependent electronic states and quantify their associated spin transport coefficients. Our findings reveal that lighter elements shift the Fermi level to regions of pronounced spin splitting, thereby increasing the magnitude of spin-current conversion, whereas heavier elements can introduce or remove near-degenerate bands that strongly affect spin-orbit coupling. In both scenarios, the fundamental chirality of Te remains robust, preserving the radial or ''collinear'' spin-momentum locking. These results not only confirm that introducing elements is a potent and feasible route for tuning spin-orbit phenomena but also offer practical guidelines for experimental efforts aiming to engineer chiral semiconductors for spin devices. By correlating element identity with specific spin-texture enhancements, this study paves the way for rationally designing next-generation spintronic components free from external magnetic fields.