Microwave spectroscopy of spin-orbit coupled states: energy detuning versus interdot coupling modulation

TL;DR

This paper investigates how AC field modulation of either interdot tunnel coupling or energy detuning affects current peaks in a spin-blockaded double quantum dot with spin-orbit interaction, highlighting more efficient detection methods for the spin-orbit gap.

Contribution

It demonstrates that modulating tunnel coupling enhances current peaks at large detuning, improving spin-orbit gap detection, and emphasizes the role of time-dependent spin-orbit interaction.

Findings

AC modulation of tunnel coupling yields stronger current peaks at large detuning.

Detection of the spin-orbit gap is more efficient with tunnel coupling modulation.

Time dependence of spin-orbit interaction significantly influences current behavior.

Abstract

We study the AC field induced current peaks of a spin blockaded double quantum dot with spin-orbit interaction. The AC field modulates either the interdot tunnel coupling or the energy detuning, and we choose the AC field frequency range to induce two singlet-triplet transitions giving rise to two current peaks. We show that for a large detuning the two current peaks can be significantly stronger when the AC field modulates the tunnel coupling, thus making the detection of the spin-orbit gap more efficient. We also demonstrate the importance of the time dependence of the spin-orbit interaction.