Transport through Double-Dots coupled to normal and superconducting leads

TL;DR

This paper investigates electron transport in double quantum dots connected to normal and superconducting leads, focusing on Andreev reflection, interference effects, and the Aharonov-Bohm phenomenon in different geometries.

Contribution

It provides a detailed analysis of transport properties in double-dot systems, highlighting interference effects and AB period reduction, which are novel insights.

Findings

Fano-type dip structures in transmission probability for parallel geometry

Interference effects induce symmetric Fano dips around the Fermi energy

AB period can be reduced from 4π to 2π in certain configurations

Abstract

We study transport through double quantum dots coupled to normal and superconducting leads, where the Andreev reflection plays a key role in determining characteristic transport properties. We shall discuss two typical cases, i.e. double dots with serial or parallel geometry. For the parallel geometry, the interference of electrons via multiple paths is induced, so that the transmission probability has Fano-type dip structures which are symmetric with respect to the Fermi energy. We also investigate the Aharonov-Bohm(AB) effect for the parallel geometry. In some particular situations, we find that the general AB period for double dots, 4$\pi$, is reduced to 2$\pi$.