Kondo resonance in an ac driven quantum dot subjected to finite bias

TL;DR

This paper investigates how a sinusoidally driven quantum dot under finite bias affects the Kondo resonance and conductance, revealing non-monotonous behavior linked to satellite and split Kondo peaks.

Contribution

It introduces a time-dependent non-crossing approximation analysis of Kondo conductance under ac driving and finite bias, highlighting novel conductance enhancement phenomena.

Findings

Average conductance deviates from monotonic reduction at specific bias and frequency conditions.

Satellite Kondo peaks overlap with split resonances, affecting conductance.

Spectral function analysis supports the interpretation of the observed behavior.

Abstract

We employ the time-dependent non-crossing approximation to study the time averaged conductance for a single electron transistor in the Kondo regime when the dot level is sinusoidally driven from its equilibrium position by means of a gate voltage in finite bias. We find that the average conductance exhibits significant deviation from the monotonous reduction when the applied bias is equal to the driving frequency of the dot level. We investigate the effect of the temperature and the driving frequency on the observed enhancement. We attribute this behaviour to the overlap of the satellite Kondo peaks with the split Kondo resonances formed at each lead's Fermi level. We display the spectral function to put our interpretation into more rigorous footing.