Interference effects in interacting quantum dots

TL;DR

This paper investigates how interference effects and electron interactions in quantum dots influence conductance features, revealing complex behaviors like multiple peaks and asymmetric line shapes, with implications for experimental observations.

Contribution

It introduces a comprehensive analysis of interference and interaction effects in quantum dots using the Hartree-Fock approximation, explaining complex conductance phenomena.

Findings

Multiple conductance peaks per dot level due to interference.

Interaction effects cause non-monotonous filling and peak broadening.

Interference determines the conductance lineshape and zero transmission points.

Abstract

In this paper we study the interplay between interference effects in quantum dots (manifested through the appearance of Fano resonances in the conductance), and interactions taken into account in the self-consistent Hartree-Fock approximation. In the non-interacting case we find that interference may lead to the observation of more than one conductance peak per dot level as a function of an applied gate voltage. This may explain recent experimental findings, which were thought to be caused by interaction effects. For the interacting case we find a wide variety of different interesting phenomena. These include both monotonous and non-monotonous filling of the dot levels as a function of an applied gate voltage, which may occur continuously or even discontinuously. In many cases a combination of the different effects can occur in the same sample. The behavior of the population influences, in turn, the conductance lineshape, causing broadening and asymmetry of narrow peaks, and determining whether there will be a zero transmission point. We elucidate the essential role of the interference between the dot levels in determining these outcomes. The effects of finite temperatures on the results are also examined.