Rashba spin-splitting of single electrons and Cooper pairs

TL;DR

This paper explores how strong spin-orbit interaction in nanostructure weak links, called 'Rashba spin splitters,' can generate novel spin-based functionalities in electronic and superconducting devices, including mechanically-controlled currents and spin-polarized Cooper pairs.

Contribution

It introduces the concept of Rashba spin splitters in weak links and reviews their potential for enabling new spintronic functionalities in nanodevices.

Findings

Mechanically-controlled spin and charge currents predicted.

Spin polarization of superconducting Cooper pairs discussed.

Role of spin-orbit interaction in weak links analyzed.

Abstract

Electric weak links, the term used for those parts of an electrical circuit that provide most of the resistance against the flow of an electrical current, are important elements of many nanodevices. Quantum dots, nanowires and nano-constrictions that bridge two bulk conductors (or superconductors) are examples of such weak links. Here we consider nanostructures where the electronic spin-orbit interaction is strong in the weak link but is unimportant in the bulk conductors, and explore theoretically the role of the spin-orbit active weak link (which we call a "Rashba spin splitter") as a source of new spin-based functionality in both normal and superconducting devices. Some recently predicted phenomena, including mechanically-controlled spin- and charge currents as well as the effect of spin polarization of superconducting Cooper pairs, are reviewed.