Engineering chiral-induced spin selectivity in an artificial topological quantum well

TL;DR

This paper demonstrates a solid-state realization of chiral-induced spin selectivity (CISS) in an engineered topological quantum well, showing controllable spin polarization through geometric chirality and dephasing, with robustness against disorder.

Contribution

It introduces a novel solid-state platform for CISS in an engineered InAs/GaSb quantum well with controllable chirality and dephasing, advancing understanding of spin-selective transport.

Findings

Chiral structures produce reversible spin polarization.

Spin polarization magnitude increases with dephasing electrodes.

Robust spin selectivity persists under strong disorder.

Abstract

Chiral-induced spin selectivity (CISS) is a striking phenomenon in which spin-unpolarized electrons become spin-polarized after traversing a chiral medium. Theoretical studies have shown that spin-orbit coupling, geometric chirality, and dephasing act cooperatively for this effect to emerge. Inspired by this, we demonstrate a solid-state realization of CISS in an engineered InAs/GaSb quantum well where geometric chirality and dephasing can be introduced controllably. Introducing a chiral structure produces a clear spin polarization whose sign reverses when the chirality is flipped, and whose magnitude grows systematically with the number of dephasing electrodes, while achiral configurations exhibit no spin selectivity. The polarization remains robust even under strong Anderson disorder, showing that the engineered chiral structures provides an intrinsically stable route to spin-selective transport. These results establish a solid-state platform in the topological quantum well system for controllably generating the CISS effect.