Spin Polarization in a AlGaAs/GaAs Quantum Point Contact with in-plane side gates

TL;DR

This paper reports the observation of spin polarization in a GaAs quantum point contact with in-plane side gates, evidenced by an anomalous conductance plateau near half the quantum of conductance, influenced by gate bias asymmetry.

Contribution

It demonstrates the emergence of spontaneous spin polarization in a side-gated GaAs QPC, a novel observation with potential for spintronic device applications.

Findings

Anomalous conductance plateau near 0.5 G0 observed.

Conductance anomaly varies with gate potential asymmetry.

Spontaneous spin polarization detected at 4.2K.

Abstract

We report the observation of an anomalous conductance plateau near G = 0.5 G0 (G0 = 2e2/h) in asymmetrically biased AlGaAs/GaAs quantum point contacts (QPCs), with in-plane side gates in the presence of lateral spin-orbit coupling. This is a signature of spin polarization in the narrow portion of the QPC. The appearance and evolution of the conductance anomaly has been studied at T=4.2K as a function of the potential asymmetry between the side gates. The observation of spontaneous spin polarization in a side-gated GaAs QPC could eventually lead to the realization of an all-electric spin-valve at tens of degrees Kelvin.