Temperature dependent deviations from ideal quantization of plateau conductances in GaAs quantum point contacts

TL;DR

This study investigates how temperature affects the quantized conductance plateaus in GaAs quantum point contacts, revealing a linear temperature dependence likely caused by intrinsic series resistance, with consistent results across multiple samples.

Contribution

It demonstrates a previously unobserved linear temperature dependence of conductance in GaAs quantum point contacts and attributes it to intrinsic series resistance effects.

Findings

Linear temperature dependence of conductance observed

Effect consistent across different samples and setups

Attribution to non-ballistic effects in the 2D-1D transition

Abstract

We present detailed experimental studies of the temperature dependence of the plateau conductance of GaAs quantum point contacts in the temperature range from 0.3 K to 10 K. Due to a strong lateral confinement produced by a shallow-etching technique we are able to observe the following unexpected feature: a linear temperature dependence of the measured mid-plateau conductance. We discuss an interpretation in terms of a temperature dependent, intrinsic series resistance, due to non-ballistic effects in the 2D-1D transition region. These results have been reproduced in several samples from different GaAs/GaAlAs heterostructures and observed in different experimental set-ups.