Electrical current and coupled electron-nuclear spin dynamics in double quantum dots

TL;DR

This paper investigates how spin-orbit interaction influences electronic transport and spin dynamics in double quantum dots, revealing characteristic current features and coupled electron-nuclear spin oscillations.

Contribution

It introduces a model linking spin-orbit effects to current behavior and explores coupled electron-nuclear spin dynamics with thermal nuclear states.

Findings

Current shows a dip at zero magnetic field or a peak at anticrossing fields.

Coupled electron-nuclear spins exhibit regular oscillations and quasi-chaotic revivals.

Derived approximate expressions for current based on state amplitudes.

Abstract

We examine electronic transport in a spin-blockaded double quantum dot. We show that by tuning the strength of the spin-orbit interaction the current flowing through the double dot exhibits a dip at zero magnetic field or a peak at a magnetic field for which the two-electron energy levels anticross. This behaviour is due to the dependence of the singlet-triplet mixing on the field and spin-orbit amplitude. We derive approximate expressions for the current as a function of the amplitudes of the states involved in the transport. We also consider an alternative model that takes into account a finite number of nuclear spins and study the resulting coupled dynamics between electron and nuclear spins. We show that if the spin ensemble is in a thermal state there are regular oscillations in the transient current followed by quasi-chaotic revivals akin to those seen in a thermal Jaynes-Cummings model.