Dynamic response of a spin-1/2 Kondo singlet

TL;DR

This paper investigates how a spin-1/2 Kondo singlet in a single electron transistor responds to microwave frequency bias, revealing non-adiabatic effects when photon energy matches the Kondo temperature, and aligns with theoretical decoherence predictions.

Contribution

It provides experimental evidence of non-adiabatic microwave response in Kondo systems and compares results with theoretical models of decoherence.

Findings

Non-adiabatic response observed at hf ≈ kBTK

Measurements align qualitatively with decoherence rate predictions

Microwave frequency influences Kondo conductance behavior

Abstract

We present a study of spin 1/2 Kondo singlets in single electron transistors under a microwave frequency bias excitation. We compare time-averaged conductance $G$ to predicted universal response with respect to microwave frequency, oscillation amplitude and the Kondo temperature and find a non-adiabatic response when the microwave photon energy $hf$ is comparable to the Kondo temperature $k_B T_K$. We show that our measurements are qualitatively consistent with the predictions for the radiation-induced decoherence rate of the Kondo spin.