Strong spin-orbit interactions and weak antilocalization in carbon doped p-type GaAs heterostructures

TL;DR

This study investigates strong spin-orbit interactions in carbon-doped p-type GaAs heterostructures, revealing significant effects like beating in oscillations and weak anti-localization, with implications for quantum device fabrication.

Contribution

It provides detailed experimental evidence of strong spin-orbit effects and quantifies the spin-split subband in p-GaAs heterostructures, advancing understanding of spin-related phenomena in these materials.

Findings

Observation of beating in Shubnikov-de Haas oscillations

Detection of weak anti-localization dip in magnetoresistance

Spin-orbit splitting is about 30% of Fermi energy

Abstract

We present a comprehensive study of the low-field magnetoresistance in carbon doped p-type GaAs/AlGaAs heterostructures aiming at the investigation of spin-orbit interaction effects. The following signatures of exceptionally strong spin-orbit interactions are simultaneously observed: a beating in the Shubnikov-de Haas oscillations, a classical positive magnetoresistance due to the presence of the two spin-split subbands, and a weak anti-localization dip in the magnetoresistance. The spin-orbit induced splitting of the heavy hole subband at the Fermi level is determined to be around 30% of the total Fermi energy. The phase coherence length of holes of around 2.5 $\mu$m at a temperature of 70 mK, extracted from weak anti-localization measurements, is promissing for the fabrication of phase-coherent p-type nanodevices.