Three Key Questions on Fractal Conductance Fluctuations: Dynamics, Quantization and Coherence

TL;DR

This paper investigates fractal conductance fluctuations in electron billiards, revealing discrepancies with existing semiclassical theory and emphasizing the importance of device geometry, potential profile, and electron trajectories.

Contribution

It introduces experimental measurements on custom devices that challenge the semiclassical Landauer-Buttiker theory, highlighting the need for more comprehensive models.

Findings

Experimental data show deviations from SLB predictions.

Device geometry and potential profiles significantly influence FCF.

Additional processes beyond SLB are necessary to explain observations.

Abstract

Recent investigations of fractal conductance fluctuations (FCF) in electron billiards reveal crucial discrepancies between experimental behavior and the semiclassical Landauer-Buttiker (SLB) theory that predicted their existence. In particular, the roles played by the billiard's geometry, potential profile and the resulting electron trajectory distribution are not well understood. We present measurements on two custom-made devices - a 'disrupted' billiard device and a 'bilayer' billiard device - designed to probe directly these three characteristics. Our results demonstrate that intricate processes beyond those proposed in the SLB theory are required to explain FCF.