Photon-induced tunability of the thermospin current in a Rashba ring

TL;DR

This paper demonstrates how Rashba spin-orbit coupling and a quantized photon mode in a cavity can be used to control the thermospin current in a quantum ring, revealing tunable spin polarization effects.

Contribution

It introduces a novel approach to modulate thermospin currents using photon fields and Rashba coupling in quantum rings, combining quantum optics with spintronics.

Findings

Rashba interaction and photon field significantly modulate spin polarization.

Degenerate energy levels correspond to destructive phase interference.

Photon field enhances spin polarization through additional kinetic momentum.

Abstract

The goal of this work is to show how the thermospin polarization current in a quantum ring changes in the presence of Rashba spin-orbit coupling and a quantized single photon mode of a cavity the ring is placed in. Employing the reduced density operator and a general master equation formalism, we find that both the Rashba interaction and the photon field can significantly modulate the spin polarization and the thermospin polarization current. Tuning the Rashba coupling constant, degenerate energy levels are formed corresponding to the Aharonov-Casher destructive phase interference in the quantum ring system. Our analysis indicates that the maximum spin polarization can be observed at the points of degenerate energy levels due to spin accumulation in the system without the photon field. The thermospin current is thus suppressed. In the presence of the cavity, the photon field leads to an additional kinetic momentum of the electron. As a result the spin polarization can be enhanced by the photon field.