Spin states and persistent currents in mesoscopic rings: spin-orbit interactions

TL;DR

This paper theoretically explores how Rashba and Dresselhaus spin-orbit interactions influence electron spin states and persistent currents in mesoscopic rings, revealing the emergence of energy gaps, current oscillation suppression, and electron localization.

Contribution

It demonstrates the combined effects of RSOI and DSOI on energy spectra and persistent currents, highlighting the formation of an effective periodic potential and its impact on electron behavior.

Findings

Energy gaps appear due to the effective periodic potential.

Oscillations of persistent charge and spin currents are weakened and smoothed.

Higher radial modes in 2D rings disrupt current oscillations.

Abstract

We investigate theoretically electron spin states in one dimensional (1D) and two dimensional (2D) hard-wall mesoscopic rings in the presence of both the Rashba spin-orbit interaction (RSOI) and the Dresselhaus spin-orbit interaction (DSOI) in a perpendicular magnetic field. The Hamiltonian of the RSOI alone is mathematically equivalent to that of the DSOI alone using an SU(2) spin rotation transformation. Our theoretical results show that the interplay between the RSOI and DSOI results in an effective periodic potential, which consequently leads to gaps in the energy spectrum. This periodic potential also weakens and smoothens the oscillations of the persistent charge current (CC) and spin current (SC) and results in the localization of electrons. For a 2D ring with a finite width, higher radial modes destroy the periodic oscillations of persistent currents.