Zero-bias anomaly and Kondo-assisted quasi-ballistic 2D transport

TL;DR

This paper investigates zero-bias anomalies in quasi-ballistic 2D electron systems, revealing Kondo-like effects and intrinsic low-energy transport phenomena through experimental measurements and scaling analysis.

Contribution

It demonstrates the observation of Kondo-assisted zero-bias anomalies and their scaling behavior in unconfined 2D systems at low electron densities, highlighting an intrinsic phenomenon.

Findings

Zero-bias conductance enhancement observed

Splitting of the anomaly at very low temperatures

Scaling behavior consistent with two-channel Kondo model

Abstract

Nonequilibrium transport measurements in mesoscopic quasi-ballistic 2D electron systems show an enhancement in the differential conductance around the Fermi energy. At very low temperatures, such a zero-bias anomaly splits, leading to a suppression of linear transport at low energies. We also observed a scaling of the nonequilibrium characteristics at low energies which resembles electron scattering by two-state systems, addressed in the framework of two-channel Kondo model. Detailed sample-to-sample reproducibility indicates an intrinsic phenomenon in unconfined 2D systems in the low electron-density regime.