Electronic structure and transport for a laser-field-irradiated quantum wire with Rashba spin-orbit coupling

TL;DR

This paper theoretically studies how an external laser field influences the electronic structure and spin-polarized transport in a Rashba spin-orbit coupled quantum wire, revealing controllable spin polarization and conductance effects.

Contribution

It introduces a theoretical framework combining nonequilibrium Green's functions to analyze laser and SOC effects on quantum wire transport, highlighting controllable spin polarization.

Findings

Laser field can modulate spin polarization rate.

External laser influences the density of states and conductance.

Interplay between laser and Rashba SOC affects transport properties.

Abstract

We investigate theoretically the electronic structure and transport for a two-level quantum wire with Rashba spin-orbit coupling (SOC) under the irradiation of an external laser field at low temperatures. The photon-induced transitions between SOC-splitted subbands with the same lateral confinement quantum numbers and between subbands with different confinement quantum number are expected. Using the method of equation of motion (EOM) for Keldysh nonequilibrium Green's functions (NGF), we examine the time-averaged density of states (DOS) and the spin polarized conductance for the system with photon polarization perpendicular to the wire direction. Through the analytical analysis and some numerical examples, the interplay effects of the external laser field and the Rashba SOC on both the DOS and the conductance of the system are demonstrated and discussed. It is found that the external laser field can adjust the spin polarization rate and the transport of the quantum wire system with some proper Rashba SOC strengths.