Quantum dissipative Rashba spin ratchets

TL;DR

This paper predicts that applying an unbiased ac drive to a dissipative, asymmetric quantum structure with Rashba spin-orbit interaction can generate a pure spin current without charge flow, even under strong dissipation.

Contribution

It introduces a novel mechanism for pure spin current generation in dissipative quantum systems with Rashba interaction, highlighting the role of asymmetry and low-temperature dynamics.

Findings

Finite stationary spin current can be generated without charge transport.

Equilibrium spin currents persist despite strong dissipation.

Pure spin ratchet behavior observed at low temperatures.

Abstract

We predict the possibility to generate a finite stationary spin current by applying an unbiased ac driving to a quasi-one-dimensional asymmetric periodic structure with Rashba spin-orbit interaction and strong dissipation. We show that under a finite coupling strength between the orbital degrees of freedom the electron dynamics at low temperatures exhibits a pure spin ratchet behavior, {\it i.e.} a finite spin current and the absence of charge transport in spatially asymmetric structures. It is also found that the equilibrium spin currents are not destroyed by the presence of strong dissipation.