Kondo Physics in the Single Electron Transistor with ac Driving

TL;DR

This paper investigates how an ac voltage influences Kondo physics in a quantum dot, revealing complex conductance behaviors across different frequency regimes due to photon-assisted tunneling and Kondo resonances.

Contribution

It introduces a time-dependent Anderson model to analyze the dynamic Kondo effect under ac driving, highlighting novel frequency-dependent conductance phenomena.

Findings

Low-frequency ac causes Kondo peak sidebands and conductance decrease

Intermediate frequencies induce oscillatory conductance due to satellite Kondo resonances

High frequencies lead to rapid conductance changes from photon-assisted tunneling

Abstract

Using a time-dependent Anderson Hamiltonian, a quantum dot with an ac voltage applied to a nearby gate is investigated. A rich dependence of the linear response conductance on the external frequency and driving amplitude is demonstrated. At low frequencies the ac potential produces sidebands of the Kondo peak in the spectral density of the dot, resulting in a logarithmic decrease in conductance over several decades of frequency. At intermediate frequencies, the conductance of the dot displays an oscillatory behavior due to the appearance of Kondo resonances of the satellites of the dot level. At high frequencies, the conductance of the dot can vary rapidly due to the interplay between photon-assisted tunneling and the Kondo resonance.