Rashba spin splitting in quantum wires

TL;DR

This paper reviews the electronic and spin transport properties of ballistic quantum wires with Rashba spin splitting, highlighting the effects of strong spin--orbit coupling and the resulting spin structures and transport phenomena.

Contribution

It provides a comprehensive overview of Rashba spin splitting effects in quantum wires, including new insights into spin structures and transport in strong coupling regimes.

Findings

Spin--precession length can be comparable to wire width in strong Rashba coupling.

Hybridization leads to unusual spin structures where motion fixes spin state.

Spin accumulation can occur without magnetic fields or ferromagnetic contacts.

Abstract

This article presents an overview of results pertaining to electronic structure, transport properties, and interaction effects in ballistic quantum wires with Rashba spin splitting. Limits of weak and strong spin--orbit coupling are distinguished, and spin properties of the electronic states elucidated. The case of strong Rashba spin splitting where the spin--precession length is comparable to the wire width turns out to be particularly interesting. Hybridization of spin--split quantum--wire subbands leads to an unusual spin structure where the direction of motion for electrons can fix their spin state. This peculiar property has important ramifications for linear transport in the quantum wire, giving rise to spin accumulation without magnetic fields or ferromagnetic contacts. A description for interacting Rashba--split quantum wires is developed, which is based on a generalization of the Tomonaga--Luttinger model.