Imaging fractional incompressible stripes in integer quantum Hall systems

TL;DR

This study uses scanning gate microscopy to unambiguously observe fractional incompressible stripes within integer quantum Hall systems, providing new insights into their spatial structure and confirming theoretical predictions.

Contribution

The paper demonstrates the direct imaging of fractional features in integer quantum Hall edge states using advanced scanning probe techniques, confirming edge-reconstruction theory.

Findings

Fractional incompressible stripes observed at filling factors 1/3, 2/5, 3/5, and 2/3.

Estimated widths of fractional stripes align with theoretical predictions.

Fractional features are consistently observed across studied samples.

Abstract

Transport experiments provide conflicting evidence on the possible existence of fractional order within integer quantum Hall systems. In fact integer edge states sometimes behave as monolithic objects with no inner structure, while other experiments clearly highlight the role of fractional substructures. Recently developed low-temperature scanning probe techniques offer today an opportunity for a deeper-than-ever investigation of spatial features of such edge systems. Here we use scanning gate microscopy and demonstrate that fractional features were unambiguously observed in every integer quantum Hall constriction studied. We present also an experimental estimate of the width of the fractional incompressible stripes corresponding to filling factors 1/3, 2/5, 3/5, and 2/3. Our results compare well with predictions of the edge-reconstruction theory.