Low Temperature Transport in Undoped Mesoscopic Structures

TL;DR

This paper investigates low-temperature electron transport in high-quality undoped GaAs/AlGaAs mesoscopic structures, revealing scattering effects and zero-bias anomalies, and detailing growth parameters for ultra-low density device fabrication.

Contribution

It introduces a method to study low-density mesoscopic regions with well-quantified impurities using optically patterned undoped heterostructures, highlighting key growth parameters.

Findings

Observation of scattering length scale signatures

Detection of zero-bias anomalies in confined regions

Identification of growth parameters for ultra-low density structures

Abstract

Using high quality undoped GaAs/AlGaAs heterostructures with optically patterned insulation between two layers of gates, it is possible to investigate very low density mesoscopic regions where the number of impurities is well quantified. Signature appearances of the scattering length scale arise in confined two dimensional regions, where the zero-bias anomaly (ZBA) is also observed. These results explicitly outline the molecular beam epitaxy growth parameters necessary to obtain ultra low density large two dimensional regions as well as clean reproducible mesoscopic devices.