Anisotropic Pauli Spin Blockade of Holes in a GaAs Double Quantum Dot

TL;DR

This paper reports on the observation of anisotropic Pauli spin blockade in hole-based GaAs double quantum dots, highlighting the role of spin-orbit coupling and g-factor anisotropy in spin transport phenomena.

Contribution

It provides the first experimental demonstration of anisotropic Pauli spin blockade in hole systems and links it to spin-orbit effects and g-factor anisotropy through numerical modeling.

Findings

Clear Pauli spin blockade observed in GaAs hole double quantum dots

Anisotropic lifting of spin blockade by magnetic field

Numerical models agree with experimental anisotropy results

Abstract

Electrically defined semiconductor quantum dots are attractive systems for spin manipulation and quantum information processing. Heavy-holes in both Si and GaAs are promising candidates for all-electrical spin manipulation, owing to the weak hyperfine interaction and strong spin-orbit interaction. However, it has only recently become possible to make stable quantum dots in these systems, mainly due to difficulties in device fabrication and stability. Here we present electrical transport measurements on holes in a gate-defined double quantum dot in a $\mathrm{GaAs/Al_xGa_{1-x}As}$ heterostructure. We observe clear Pauli spin blockade and demonstrate that the lifting of this spin blockade by an external magnetic field is highly anisotropic. Numerical calculations of heavy-hole transport through a double quantum dot in the presence of strong spin-orbit coupling show quantitative agreement with experimental results and suggest that the observed anisotropy can be explained by both the anisotropic effective hole g-factor and the surface Dresselhaus spin-orbit interaction.