Evidence for a $\nu=5/2$ Fractional Quantum Hall Nematic State in Parallel Magnetic Fields

TL;DR

This study provides evidence that the fractional quantum Hall state at filling factor 5/2 exhibits nematic behavior under parallel magnetic fields, characterized by significant resistance anisotropy without gap reduction, indicating a nematic phase.

Contribution

First experimental observation of a nematic phase in the fractional quantum Hall state at 5/2 filling factor under parallel magnetic fields.

Findings

Resistance anisotropy increases with parallel magnetic field.

Energy gap remains constant despite anisotropy.

Data supports the existence of a fractional quantum Hall nematic phase.

Abstract

We report magneto-transport measurements for the fractional quantum Hall state at filling factor $\nu=$ 5/2 as a function of applied parallel magnetic field ($B_{||}$). As $B_{||}$ is increased, the 5/2 state becomes increasingly anisotropic, with the in-plane resistance along the direction of $B_{||}$ becoming more than 30 times larger than in the perpendicular direction. Remarkably, the resistance anisotropy ratio remains constant over a relatively large temperature range, yielding an energy gap which is the same for both directions. Our data are qualitatively consistent with a fractional quantum Hall \textit{nematic} phase.