Cascade of fractional quantum Hall states in 2D system

TL;DR

This study reveals new fractional quantum Hall states in ultra-high-quality GaAs/AlGaAs quantum wells, expanding understanding of topological phases driven by strong electron correlations.

Contribution

It reports the discovery of new FQH states at filling factors 17/33 and 15/31 and analyzes their origins within composite fermion theory.

Findings

New FQH states observed at 17/33 and 15/31.

Disparate effects of in-plane magnetic field on FQH states.

Most fractions explained by non-interacting composite fermions.

Abstract

The observation of the fractional quantum Hall (FQH) effect in 2D electron gases ushered in investigations of topological phases driven by strong electron correlations. Their remarkable features include fractionalized elementary excitations, gapless boundary states, and non-trivial quantum entanglement patterns. Thanks to persistent efforts in the building of new platforms and making higher-quality samples, a diverse plethora of FQH states have been unveiled in experiments. We report a systematic study of ultrahigh-quality GaAs/AlGaAs quantum wells with mobility up to 3.7*10^7 cm^2/V/s using quantum transport measurements in nuclear adiabatic demagnetization and dilution refrigerators down to 1 mK. In addition to many FQH states that have already been identified in previous work, new longitudinal resistance dips are observed at filling factors 17/33 and 15/31. The application of an in-plane magnetic field causes disparate variations of the FQH states. The theoretical foundation of these states is discussed in the framework of composite fermion theory. While most fractions can be explained as non-interacting composite fermions forming integer quantum Hall states, a few states correspond to FQH states of composite fermions that arise from residual interaction between them. We summarize the observed fractions in the range of 0 < {\nu} < 2 and propose a pattern to account for their experimental appearance that provides an intuitive picture about the relative strengths of different FQH states.