Interplay of mesoscopic and Kondo effects for transmission amplitude of few-level quantum dots

TL;DR

This paper investigates how mesoscopic effects and Kondo correlations influence the transmission amplitude's magnitude and phase in multi-level quantum dots, revealing temperature-dependent behaviors and stationary points affected by neighboring levels.

Contribution

It provides a detailed analysis of the interplay between mesoscopic effects and Kondo physics in multi-level quantum dots, highlighting conditions for stationary phase points and their dependence on mesoscopic parameters.

Findings

Kondo plateaus vanish with increasing temperature.

Stationary points in transmission phase are found at specific gate voltages.

Neighboring levels influence the position of stationary points.

Abstract

The magnitude and phase of the transmission amplitude of a multi-level quantum dot is calculated for the mesoscopic regime of level spacing large compared to level width. The interplay between Kondo correlations and the influence by neighboring levels is discussed. As in the single-level case, the Kondo plateaus of magnitude and phase disappear with increasing temperature. At certain gate voltages, ``stationary'' points are found at which the transmission phase is independent of temperature. Depending on the mesoscopic parameters of the adjacent levels (like relative sign and magnitude of tunneling matrix elements), the stationary points are shifted to or repelled by the neighboring level.