Spin-orbital and spin Kondo effects in parallel coupled quantum dots

TL;DR

This paper investigates the complex many-body effects, interference phenomena, and spintronic applications in parallel-coupled quantum dots using a mean-field slave boson approach across various regimes.

Contribution

It provides a comprehensive analysis of electron correlations, interference effects, and spin control in quantum dots, including proposals for spintronic devices.

Findings

Control of current polarization via interference and correlations.

Identification of regimes for Kondo effects in quantum dots.

Proposals for double dot spin valve and electrically tunable spin filter.

Abstract

Strong electron correlations and interference effects are discussed in parallel-coupled single-level and orbitally doubly degenerate quantum dots. The finite-U mean-field slave boson approach is used to study many-body effects. The analysis is carried out in a wide range of parameter space including both atomic-like and molecular-like Kondo regimes and taking into account various perturbations, like interdot tunneling, interdot interaction, mixing of the electrode channels and exchange interaction. We also discuss the influence of singularities of electronic structure and the impact of polarization of electrodes. Special attention is paid to potential spintronic applications of these systems showing how current polarization can be controlled by adjusting interference conditions and correlations by gate voltage. Simple proposals of double dot spin valve and bipolar electrically tunable spin filter are presented.