Fano and Dicke effects and spin polarization in a double Rashba-ring system side coupled to a quantum wire

TL;DR

This paper investigates a double Rashba-ring system side-coupled to a quantum wire, demonstrating how Fano and Dicke effects can be exploited to achieve efficient spin filtering with enhanced polarization capabilities.

Contribution

The study provides analytical expressions for conductance and spin polarization in a double Rashba-ring system, showing improved spin filtering compared to single-ring configurations.

Findings

System exhibits significant spin polarization due to Fano and Dicke effects.

Double-ring setup outperforms single-ring in spin polarization efficiency.

Analytical formulas enable design of spin filters with small spin-orbit interaction.

Abstract

The electronic transport in a system of two quantum rings side-coupled to a quantum wire is studied via a single-band tunneling tight-binding Hamiltonian. We derived analytical expressions for the conductance and spin polarization when the rings are threaded by magnetic fluxes with Rashba spin-orbit interaction. We show that by using the Fano and Dicke effects this system can be used as an efficient spin-filter even for small spin orbit interaction and small values of magnetic flux. We compare the spin-dependent polarization of this design and the polarization obtained with one ring side coupled to a quantum ring. As a main result, we find better spin polarization capabilities as compared to the one ring design