Coulomb-exchange effects in nanowires with spin splitting due to a radial electric field

TL;DR

This paper theoretically investigates how Coulomb exchange interactions influence spin splitting effects in cylindrical nanowires with Rashba spin-orbit coupling, revealing significant impacts on quasiparticle mass and exchange energy.

Contribution

It provides new insights into the interplay between Coulomb exchange and spin-orbit coupling in quantum wires, highlighting effects on quasiparticle properties.

Findings

Exchange suppresses quasiparticle effective mass by up to 15%.

Finite spin splitting increases mass suppression significantly.

Spin-orbit coupling modestly reduces exchange energy by about 1%.

Abstract

We present a theoretical study of Coulomb exchange interaction for electrons confined in a cylindrical quantum wire and subject to a Rashba-type spin-orbit coupling with radial electric field. The effect of spin splitting on the single-particle band dispersions, the quasiparticle effective mass, and the system's total exchange energy per particle are discussed. Exchange interaction generally suppresses the quasiparticle effective mass in the lowest nanowire subband, and a finite spin splitting is found to significantly increase the magnitude of the quasiparticle-mass suppression (by upto 15\% in the experimentally relevant parameter regime). In contrast, spin-orbit coupling causes a modest (1\%-level) reduction of the magnitude of the exchange energy per particle. Our results shed new light on the interplay of spin-orbit coupling and Coulomb interaction in quantum-confined systems, including those that are expected to host exotic quasiparticle excitations.