Flux-dependent Kondo temperature in an Aharonov-Bohm interferometer with an in-line quantum dot

TL;DR

This paper investigates how magnetic flux influences the Kondo temperature in an Aharonov-Bohm interferometer with an embedded quantum dot, revealing flux-dependent effects and challenges in measuring the quantum dot's transmission phase shift.

Contribution

It demonstrates that the Kondo temperature varies with magnetic flux in an ABI, causing finite-size effects that impact conductance and phase shift measurements.

Findings

Kondo temperature depends strongly on magnetic flux.

Finite-size effects lead to conductance plateaus.

Flux can hinder detection of the Kondo phase shift.

Abstract

An Aharonov-Bohm interferometer (ABI) carrying a quantum dot on one of its arms is analyzed. It is found that the Kondo temperature of the device depends strongly on the magnetic flux penetrating the ring. As a result, mesoscopic finite-size effects appear when the Kondo temperature of the dot on the ABI is significantly smaller than the nominal one of the quantum dot (when not on the interferometer), leading to plateaus in the finite-temperature conductance as function of the flux. The possibility to deduce the transmission phase shift of the quantum dot from measurements of the ABI conductance when it is opened (i.e., is connected to more than two leads) is examined, leading to the conclusion that finite-size effects, when significant, may hinder the detection of the Kondo phase shift