Spin interference and Fano effect in electron transport through a mesoscopic ring side-coupled with a quantum dot

TL;DR

This paper explores how Rashba spin-orbit interaction influences electron transport in a mesoscopic ring with a quantum dot, revealing Fano resonances, spin interference effects, and the generation of spin-polarized currents.

Contribution

It demonstrates the combined effects of Fano resonance and spin interference in a mesoscopic ring with a quantum dot under Rashba spin-orbit interaction, including control via gate voltage and magnetic flux.

Findings

Fano resonance line shape appears near the Fermi energy.

Electrical gate voltage can modulate the transmission strongly.

Magnetic flux induces spin-polarized current despite unpolarized incident current.

Abstract

We investigate the electron transport through a mesoscopic ring side-coupled with a quantum dot(QD) in the presence of Rashba spin-orbit(SO) interaction. It is shown that both the Fano resonance and the spin interference effects play important roles in the electron transport properties. As the QD level is around the Fermi energy, the total conductance shows typical Fano resonance line shape. By applying an electrical gate voltage to the QD, the total transmission through the system can be strongly modulated. By threading the mesoscopic ring with a magnetic flux, the time-reversal symmetry of the system is broken, and a spin polarized current can be obtained even though the incident current is unpolarized.