A quantitative study of spin-flip co-tunneling transport in a quantum dot

TL;DR

This study provides detailed measurements of spin-flip co-tunneling in a quantum dot, comparing experimental data with microscopic theory, and finds excellent agreement without adjustable parameters, enhancing understanding of spin-dependent transport.

Contribution

It offers a quantitative comparison between experimental data and microscopic theory for spin-flip co-tunneling in quantum dots, validating the theoretical model.

Findings

Good quantitative agreement with theory across multiple states

No adjustable parameters needed for the model

Phenomenological analysis aligns with microscopic predictions

Abstract

We report detailed transport measurements in a quantum dot in a spin-flip co-tunneling regime, and a quantitative comparison of the data to microscopic theory. The quantum dot is fabricated by lateral gating of a GaAs/AlGaAs heterostructure, and the conductance is measured in the presence of an in-plane Zeeman field. We focus on the ratio of the nonlinear conductance values at bias voltages exceeding the Zeeman threshold, a regime that permits a spin flip on the dot, to those below the Zeeman threshold, when the spin flip on the dot is energetically forbidden. The data obtained in three different odd-occupation dot states show good quantitative agreement with the theory with no adjustable parameters. We also compare the theoretical results to the predictions of a phenomenological form used previously for the analysis of non-linear co-tunneling conductance, specifically the determination of the heterostructure g-factor, and find good agreement between the two.