Enhanced Zeeman splitting in Ga0.25In0.75As quantum point contacts

TL;DR

This paper reports an experimental study of Zeeman splitting in Ga0.25In0.75As quantum point contacts, revealing enhanced g-factors and large subband spacings that are promising for spin-resolved transport at higher temperatures.

Contribution

The study demonstrates significantly enhanced Zeeman splitting and large subband spacings in Ga0.25In0.75As quantum point contacts, advancing understanding of spin properties in this material system.

Findings

Zeeman splitting is enhanced in Ga0.25In0.75As QPCs.

g-factor varies from 3.8 to 5.8 across subbands.

Subband spacings exceed 10 meV, enabling higher temperature operation.

Abstract

The strength of the Zeeman splitting induced by an applied magnetic field is an important factor for the realization of spin-resolved transport in mesoscopic devices. We measure the Zeeman splitting for a quantum point contact etched into a Ga0.25In0.75As quantum well, with the field oriented parallel to the transport direction. We observe an enhancement of the Lande g-factor from |g*|=3.8 +/- 0.2 for the third subband to |g*|=5.8 +/- 0.6 for the first subband, six times larger than in GaAs. We report subband spacings in excess of 10 meV, which facilitates quantum transport at higher temperatures.