Spin-Orbit Coupling, Antilocalization, and Parallel Magnetic Fields in Quantum Dots

TL;DR

This paper studies how spin-orbit coupling affects electron transport in GaAs quantum dots, showing size-dependent antilocalization effects and magnetic field suppression, with in situ control demonstrated via gating.

Contribution

It provides experimental evidence of size-dependent antilocalization suppression and demonstrates gate-controlled crossover between weak localization and antilocalization in quantum dots.

Findings

Antilocalization prominent in large dots, suppressed in small dots

Parallel magnetic fields suppress antilocalization and weak localization

Gate control enables crossover between localization regimes

Abstract

We investigate antilocalization due to spin-orbit coupling in ballistic GaAs quantum dots. Antilocalization that is prominent in large dots is suppressed in small dots, as anticipated theoretically. Parallel magnetic fields suppress both antilocalization and also, at larger fields, weak localization, consistent with random matrix theory results once orbital coupling of the parallel field is included. In situ control of spin-orbit coupling in dots is demonstrated as a gate-controlled crossover from weak localization to antilocalization.