Interference effects in transport across a single incompressible strip at the edge of the fractional quantum Hall system

TL;DR

This study experimentally explores interference effects in transport across incompressible strips at the edge of a fractional quantum Hall system using a Fabry-Perot interferometer, revealing electron-based interference at certain fractional fillings.

Contribution

It provides new experimental evidence of interference phenomena in fractional quantum Hall edge states, highlighting the role of electrons even at fractional fillings.

Findings

Interference oscillations observed at ν_c=1, 4/3, 2/3

No interference detected at ν_c=1/3

Interference period depends on effective interferometer area

Abstract

We experimentally investigate interference effects in transport across a single incompressible strip at the edge of the quantum Hall system by using a Fabry-Perot type interferometer. We find the interference oscillations in transport across the incompressible strips with local filling factors $\nu_c=1, 4/3, 2/3$ even at high imbalances, exceeding the spectral gaps. In contrast, there is no sign of the interference in transport across the principal Laughlin $\nu_c=1/3$ incompressible strip. This indicates, that even at fractional $\nu_c$, the interference effects are caused by "normal" electrons. The oscillation's period is determined by the effective interferometer area, which is sensitive to the filling factors because of screening effects.