Cotunneling Spectroscopy in Few-Electron Quantum Dots

TL;DR

This paper explores inelastic cotunneling in few-electron quantum dots, revealing singlet-triplet splitting, a non-equilibrium Kondo effect, and insights into orbital correlations and entanglement through transport measurements.

Contribution

It introduces a detailed analysis of cotunneling spectroscopy in strongly coupled quantum dots, highlighting new observations of Kondo effects and entanglement parameters.

Findings

Measured two-electron singlet-triplet splitting

Observed non-equilibrium Kondo effect

Extracted orbital correlations and entanglement parameters

Abstract

Few-electron quantum dots are investigated in the regime of strong tunneling to the leads. Inelastic cotunneling is used to measure the two-electron singlet-triplet splitting above and below a magnetic field driven singlet-triplet transition. Evidence for a non-equilibrium two-electron singlet-triplet Kondo effect is presented. Cotunneling allows orbital correlations and parameters characterizing entanglement of the two-electron singlet ground state to be extracted from dc transport.