Excitons in Fractional Quantum Hall Effect

Naiyuan J. Zhang, Ron Q. Nguyen, Navketan Batra, Xiaoxue Liu, Kenji Watanabe, Takashi Taniguchi, D. E. Feldman, J. I. A. Li

Published 2024-07-25Version 1

An exciton is a Coulomb-driven bound state, which normally consists of an electron and a hole. Under the influence of charge fractionalization, an exotic construction of exciton arises from pairing between fractional particle and hole charge. Despite numerous theoretical considerations, experimental realization of fractional excitons remains largely unexplored. In this work, we report hallmark transport signatures of excitonic pairing that coexists with fractional quantum Hall effect states. Such coexistence reveals a new construction for fractional quantum Hall effect, where exciton pairing plays an essential role in defining the underlying wavefunction. By surveying the two-dimensional phase space defined by Landau-level filling and layer imbalance, we describe transitions between ground states with distinct exciton compositions. The hierarchical behavior of the excitonic sequence provides potential evidence for excitons with fractional charge constituents, which obey fermionic and anyonic statistics.