Electronic states and persistent currents in nanowire quantum ring

TL;DR

This paper introduces a new model for a nanowire quantum ring incorporating spin-orbit coupling, revealing unique persistent current behaviors and the possibility of pure spin currents controlled by magnetic field and gate voltage.

Contribution

A novel quantum ring model inside a nanowire with Rashba and Dresselhaus SOC, analyzing energy spectra and persistent currents with implications for spintronics.

Findings

SOC causes anticrossings in energy spectrum.

Magnetic field and gate control can generate pure spin currents.

Unusual persistent current behaviors due to SOC effects.

Abstract

The new model of a quantum ring (QR) defined inside a nanowire (NW) is proposed. The one-particle Hamiltonian for electron in [111]-oriented NW QR is constructed taking into account both Rashba and Dresselhaus spin-orbit coupling (SOC). The energy levels as a function of magnetic field are found using the exact numerical diagonalization. The persistent currents (both charge and spin) are calculated. The specificity of SOC and arising anticrossings in energy spectrum lead to unusual features in persistent current behavior. The variation of magnetic field or carrier concentration by means of gate can lead to pure spin persistent current with the charge current being zero.