Single- and multi-mode Fabry-P\'erot interference in suspended graphene

TL;DR

This study demonstrates high-quality Fabry-Pérot interference in suspended graphene, revealing coexistence of longitudinal and transverse resonances and providing insights into Fermi velocity renormalization due to many-body interactions.

Contribution

The paper presents a detailed Fourier analysis of interference patterns in suspended graphene, uncovering the coexistence of multiple resonances and insights into many-body effects on Fermi velocity.

Findings

Identification of overlapping interference patterns corresponding to different resonances

Correlation of interference patterns with device geometry ratios

Evidence of Fermi velocity renormalization due to many-body interactions

Abstract

Phase coherence of charge carriers leads to electron-wave interference in ballistic mesoscopic conductors. In graphene, such Fabry-P\'erot-like interference has been observed, but a detailed analysis has been complicated by the two-dimensional nature of conduction, which allows for complex interference patterns. In this work, we have achieved high-quality Fabry-P\'erot interference in a suspended graphene device, both in conductance and in shot noise, and analyzed their structure using Fourier transform techniques. The Fourier analysis reveals two sets of overlapping, coexisting interferences, with the ratios of the diamonds being equal to the width to length ratio of the device. We attribute these sets to a unique coexistence of longitudinal and transverse resonances, with the longitudinal resonances originating from the bunching of modes with low transverse momentum. Furthermore, our results give insight into the renormalization of the Fermi velocity in suspended graphene samples, caused by unscreened many-body interactions.