Quantum Hall nano-interferometer in graphene

TL;DR

This paper investigates graphene-based quantum Hall nano-interferometers using scanning gate spectroscopy, demonstrating that localized states hinder interference and that a simple non-interacting Fabry-Perot model can explain the observed phenomena.

Contribution

It shows that localized states negatively impact interference in graphene quantum Hall interferometers and that a non-interacting model suffices to describe the system.

Findings

Localized states impair interference in graphene QHIs.

A simple Fabry-Perot model explains the QHI behavior.

Interference can be observed without Coulomb interactions.

Abstract

Quantum Hall edge states offer avenues for quasiparticle interferometry, provided that the ratio between phase coherence length and quantum Hall interferometer (QHI) size is large enough. Maximizing this ratio by shrinking the QHI area favors Coulomb interactions, impairing clear interferences observation. Here, we use scanning gate spectroscopy to probe interference regime in antidots-based graphene nano-QHIs, free of localized states (LS). A simple Fabry-Perot model, without Coulomb interaction, reproduces the QHI phenomenology, even in the smallest QHI, highlighting the LS detrimental role.