Three-terminal transport through a quantum dot in the Kondo regime: Conductance, dephasing, and current-current correlations

TL;DR

This paper explores the complex nonequilibrium transport phenomena in a three-terminal quantum dot exhibiting Kondo effects, analyzing how external parameters influence conductance, shot noise, and current correlations.

Contribution

It provides new insights into the behavior of current correlations and the effects of magnetic fields and dephasing in a three-terminal Kondo quantum dot system.

Findings

Current correlations are highly sensitive to magnetic fields.

Shot noise depends nontrivially on the third lead voltage.

Dephasing affects the Kondo resonance in multi-terminal setups.

Abstract

We investigate the nonequilibrium transport properties of a three-terminal quantum dot in the strongly interacting limit. At low temperatures, a Kondo resonance arises from the antiferromagnetic coupling between the localized electron in the quantum dot and the conduction electrons in source and drain leads. It is known that the local density of states is accessible through the differential conductance measured at the (weakly coupled) third lead. Here, we consider the multiterminal current-current correlations (shot noise and cross correlations measured at two different terminals). We discuss the dependence of the current correlations on a number of external parameters: bias voltage, magnetic field and magnetization of the leads. When the Kondo resonance is split by fixing the voltage bias between two leads, the shot noise shows a nontrivial dependence on the voltage applied to the third lead. We show that the cross correlations of the current are more sensitive than the conductance to the appearance of an external magnetic field. When the leads are ferromagnetic and their magnetizations point along opposite directions, we find a reduction of the cross correlations. Moreover, we report on the effect of dephasing in the Kondo state for a two-terminal geometry when the third lead plays the role of a fictitious voltage probe.