Current-Conserving Aharonov-Bohm Interferometry with Arbitrary Spin Interactions

TL;DR

This paper introduces a charge-conserving scattering matrix formalism for spin interactions in Aharonov-Bohm interferometers, revealing spin-flip scattering can occur at nonmagnetic junctions due to non-orthogonal spin states.

Contribution

It develops a general formalism ensuring charge conservation with arbitrary spin interactions and applies it to analyze spin switching behavior in semiconductor ring interferometers.

Findings

Spin-flip scattering occurs at nonmagnetic junctions with non-orthogonal spin states.

The formalism predicts conditional and unconditional spin switching in different coupling regimes.

Charge conservation is guaranteed at junctions with arbitrary spin interactions.

Abstract

We propose a general scattering matrix formalism that guarantees the charge conservation at junctions between conducting arms with arbitrary spin interactions. By using our formalism, we find that the spin-flip scattering can happen even at nonmagnetic junctions if the spin eigenstates in arms are not orthogonal. We apply our formalism to the Aharonov-Bohm interferometer consisting of $n$-type semiconductor ring with both the Rashba spin-orbit coupling and the Zeeman splitting. We discuss the characteristics of the interferometer as conditional/unconditional spin switch in the weak/strong-coupling limit, respectively.