Enhanced Current-Induced Spin Polarization in Ultrathin Chiral Nanowires

Abstract

Current-induced spin polarization (CISP) has recently emerged as an attractive route for generating spin-polarized current for spintronics, yet to achieve large and robust CISP remains challenging. Here, by combining first-principles and tight-binding analyses, we reveal that CISP in chiral tellurium (Te) could be significantly enhanced in the one-dimensional (1D) form of ultrathin nanowires. Compared to bulk Te, quantum confinement widens the band gap and amplifies the spin polarization as the diameter of the nanowire shrinks. Quantum transport simulations explicitly demonstrate that the CISP in Te nanowires increases with reduced diameters, reaching a high value of ∼65% in a single Te chain. We attribute this CISP enhancement to the synergistic effects of nanowire size and spin-orbit coupling (SOC), where SOC comprises atomic and structural components, offering further tunability via elemental substitution and mechanical strain. This study demonstrates the potential to achieve high CISP in chiral nanomaterials, valuable for future design and development of high-performance spintronic devices without the requirement of a ferromagnetic contact or an external magnetic field.