Electron and nuclear spin properties of the nanohole-filled GaAs/AlGaAs quantum dots

TL;DR

This study investigates the spin properties of GaAs/AlGaAs nanohole-filled quantum dots, revealing nearly zero electron g-factor, high nuclear spin polarization, and long nuclear spin lifetimes, which are promising for quantum information applications.

Contribution

The paper provides new insights into the spin characteristics of nanohole-filled quantum dots, including near-zero electron g-factor and long nuclear spin coherence times.

Findings

Electron g-factor less than 0.05 enabling electric spin control

Nuclear spin polarization up to 60% achieved

Nuclear spin lifetimes exceeding 1000 seconds

Abstract

GaAs/AlGaAs quantum dots grown by in-situ droplet etching and nanohole infilling offer a combination of strong charge confinement, optical efficiency, and spatial symmetry required for polarization entanglement and spin-photon interface. Here we study spin properties of such dots. We find nearly vanishing electron $g$-factor ($g_e<0.05$), providing a route for electrically driven spin control schemes. Optical manipulation of the nuclear spin environment is demonstrated with nuclear spin polarization up to $60\%$ achieved. NMR spectroscopy reveals the structure of two types of quantum dots and yields the small magnitude of residual strain $\epsilon_b<0.02\%$ which nevertheless leads to long nuclear spin lifetimes exceeding 1000 s. The stability of the nuclear spin environment is advantageous for applications in quantum information processing.