Electron g-factor determined for quantum dot circuit fabricated from (110)-oriented GaAs quantum well

TL;DR

This paper demonstrates a double quantum dot circuit on a (110)-oriented GaAs quantum well, measuring a significantly lower in-plane electron g-factor compared to standard (001) substrates, with implications for spintronic device design.

Contribution

It reports the first measurement of the electron g-factor in a quantum dot circuit fabricated from (110)-oriented GaAs quantum well, highlighting substrate orientation effects on spin properties.

Findings

Electron g-factor ~0.1 for (110) GaAs quantum well.

g-factor is about four times lower than in (001) GaAs.

Hyperfine interactions influence spin blockade behavior.

Abstract

The choice of substrate orientation for semiconductor quantum dot circuits offers opportunities for tailoring spintronic properties such as g-factors for specific functionality. In this letter, we demonstrate the operation of a few-electron double quantum dot circuit fabricated from a (110)-oriented GaAs quantum well. We estimate the in-plane electron g-factor from the profile of the enhanced inter-dot tunneling (leakage) current near zero magnetic field. Spin-blockade due to Pauli exclusion can block inter-dot tunneling. However, this blockade becomes inactive due to hyperfine interaction mediated spin flip-flop processes between electron spin states and the nuclear spin of the host material. The g-factor of absolute value ~0.1 found for a magnetic field parallel to the direction [11(bar)0], is approximately a factor of four lower than that for comparable circuits fabricated from material grown on widely-employed standard (001) GaAs substrates, and is in line with reported values determined by purely optical means for quantum well structures grown on (110) GaAs substrates.