Charge and spin polarized currents in mesoscopic rings with Rashba spin-orbit interactions coupled to an electron reservoir

TL;DR

This paper investigates how Rashba spin-orbit coupling and reservoir interactions influence charge and spin persistent currents in mesoscopic rings, revealing how these currents can be controlled and protected under various conditions.

Contribution

It provides an exact density of states calculation and analyzes the effects of reservoir coupling and temperature on persistent currents in mesoscopic rings with Rashba spin-orbit interaction.

Findings

Persistent currents degrade uniformly with reservoir coupling.

Temperature affects currents nonuniformly, depending on Fermi sea depth.

Rashba coupling can tailor flux regimes for charge and spin currents.

Abstract

The electronic states of a mesoscopic ring are assessed in the presence of Rashba Spin Orbit coupling and a $U(1)$ gauge field. Spin symmetric coupling to an ideal lead is implemented following B\"uttiker's voltage probe. The exact density of states is derived using the reservoir uncoupled eigenstates as basis functions mixed by the reservoir coupling. The decay time of uncoupled electron eigenstates is derived by fitting the broadening profiles. The spin and charge persistent currents are computed in the presence of the SO interaction and the reservoir coupling for two distinct scenarios of the electron filling fraction. The degradation of the persistent currents depends uniformly on the reservoir coupling but nonuniformly in temperature, the latter due to the fact that currents emerge from different depths of the Fermi sea, and thus for some regimes of flux, they are provided with a protective gap. Such flux regimes can be tailored by the SO coupling for both charge and spin currents.