Observation of Incompressibility at $\nu=4/11$ and $\nu=5/13$

TL;DR

This study observes incompressibility at fractional quantum Hall states $ u=4/11$ and $ u=5/13$, providing evidence for potential new topological orders in the fractional quantum Hall regime.

Contribution

First experimental observation of incompressibility at $ u=4/11$ and $ u=5/13$, advancing understanding of emergent topological states in fractional quantum Hall systems.

Findings

Incompressibility observed at $ u=4/11$ and $ u=5/13$

States at $ u=6/17$ and $3/8$ remain compressible

Supports the existence of novel topological orders

Abstract

The region of filling factors $1/3<\nu<2/5$ is predicted to support new types of fractional quantum Hall states with topological order different from that of the Laughlin-Jain or the Moore-Read states. Incompressibility is a necessary condition for the formation of such novel topological states. We find that at 6.9~mK incompressibility develops only at $\nu=4/11$ and $5/13$, while the states at $\nu=6/17$ and $3/8$ remain compressible. Our observations at $\nu=4/11$ and $5/13$ are first steps towards understanding emergent topological order in these fractional quantum Hall states.