Single-photon controlled thermospin transport in a resonant ring-cavity system

TL;DR

This paper models a quantum ring-cavity system to study how single-photon interactions influence thermospin transport, revealing control mechanisms via Rashba coupling and photon resonance effects.

Contribution

It introduces a quantum master equation approach to analyze thermospin transport in a cavity-coupled quantum ring with photon interactions, highlighting the effects of photon resonance and Rashba coupling.

Findings

Maximum spin polarization at Rashba coupling corresponding to Aharonov-Casher interference

Rabi splitting observed near photon resonance

Photon replica states reduce thermospin current

Abstract

Cavity-coupled nanoelectric devices hold great promise for quantum technology based on coupling between electron-spins and photons. In this study, we approach the description of these effects through the modeling of a nanodevice using a quantum master equation. We assume a quantum ring is coupled to two external leads with different temperatures and embedded in a cavity with a single photon mode. Thermospin transport of the ring-cavity system is investigated by tuning the Rashba coupling constant and the electron-photon coupling strength. In the absence of the cavity, the temperature gradient of the leads causes a generation of a thermospin transport in the ring system. It is observed that the induced spin polarization has a maximum value at the critical value of the Rashba coupling constant corresponding to the Aharonov-Casher destructive interference, where the thermospin current is efficiently suppressed. Embedded in a photon cavity with the photon energy close to a resonance with the energy spacing between lowest states of the quantum ring, a Rabi splitting in the energy spectrum is observed. Furthermore, photon replica states are formed leading to a reduction in the thermospin current.