Non-Kondo zero-bias anomaly in quantum wires

TL;DR

This paper investigates zero-bias anomalies in quantum wires and finds that they do not behave as expected from Kondo physics, suggesting a different underlying mechanism.

Contribution

The study provides experimental evidence that zero-bias anomalies in quantum wires are not due to Kondo correlations, challenging previous assumptions.

Findings

ZBAs do not split as magnetic field increases up to 10 T

Some ZBAs split less than expected from Kondo effect

ZBAs can revert to a single peak when the constriction is laterally moved

Abstract

It has been suggested that a zero-bias conductance peak in quantum wires signifies the presence of Kondo spin-correlations, which might also relate to an intriguing 1D spin-effect known as the 0.7 structure. These zero-bias anomalies (ZBA) are strongly temperature dependent, and have been observed to split into two peaks in magnetic field, both signatures of Kondo correlations in quantum dots. We present data in which ZBAs in general do not split as magnetic field is increased up to 10 T. A few of our ZBAs split in magnetic field but by significantly less than the Kondo splitting value, and evolve back to a single peak upon moving the 1D constriction laterally. The ZBA therefore does not appear to have a Kondo origin, and instead we propose a simple phenomenological model to reproduce the ZBA which is in agreement mostly with observed characteristics.