Moir\'e Assisted Fractional Quantum Hall State Spectroscopy

TL;DR

This paper proposes using moiré pattern-induced periodic potentials to enable optical spectroscopy of intra-Landau level excitations in fractional quantum Hall systems, which are otherwise inaccessible.

Contribution

It introduces a novel method leveraging moiré patterns to probe fractional quantum Hall states optically, supported by theoretical analysis and recent experimental observations.

Findings

Moiré patterns enable optical access to intra-Landau level excitations.

Theoretical analysis confirms the feasibility of this approach.

Recent experiments in moiré graphene support the proposed method.

Abstract

Intra-Landau level excitations in the fractional quantum Hall regime are not accessible via optical absorption measurements. We point out that optical probes are enabled by the periodic potentials produced by a moir\'e pattern. Our observation is motivated by the recent observations of fractional quantum Hall incompressible states in moir\'e-patterned graphene on a hexagonal boron nitride substrate, and is theoretically based on $f-$sum rule considerations supplemented by a perturbative analysis of the influence of the moir\'e potential on many-body states.