Observation of fractional quantum anomalous Hall effect

ORAL · Invited

Abstract

The synergy of topology, strong correlations, and spontaneous symmetry breaking can give rise to exotic quantum states of matter. A celebrated example is the rationally designed flat Chern band, which hosts fractional Chern insulators. These insulators can exhibit the fractional quantum anomalous Hall effect(FQAHE), which is the lattice analog of the fractional quantum Hall effect at zero magnetic field without Landau level formation. In this talk, I will present the experimental observation of high-temperature FQAHE in twisted MoTe2 bilayer, using combined magneto-optical spectroscopy and transport measurements. Additionally, I will present an anomalous Hall state around the filling factor of -1/2, the leading candidate for which is a composite Fermi liquid state. Notably, the states associated with the FQAH and associated effects can be electrically tuned into a variety of topologically trivial phases. These results mark a promising direction for the investigation of charge fractionalization and anyon statistics at zero magnetic field and elevated temperature.

* Measurements of the FQAH states are supported by DoE BES under award DE-SC0018171. Measurements of the integer QAH state are supported by the AFOSR FA9550-21-1-0177. Device fabrication and electrical transport measurements are partially supported by the Center on Programmable Quantum Materials, an Energy Frontier Research Center funded by DOE BES, under award DE-SC0019443. The understanding of magnetism and the topological phase diagram is partially supported by AFOSR Multidisciplinary University Research Initiative (MURI) programme, grant no. FA9550-19-1-0390. We also acknowledge the use of the facilities and instrumentation supported by the NSF MRSEC DMR-1719797.This research acknowledges the use of the millikelvin optoelectronic quantum material laboratory supported by the M. J. Murdock Charitable Trust.

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Publication: Cai, J., Anderson, E., Wang, C. et al. Signatures of fractional quantum anomalous Hall states in twisted MoTe2.
Park, H., Cai, J., Anderson, E. et al. Observation of fractionally quantized anomalous Hall effect. Nature 622, 74–79 (2023).
Eric Anderson et al. ,Programming correlated magnetic states with gate-controlled moiré geometry.Science381,325-330(2023).

Presenters

  • Jiaqi Cai

    University of Washington

Authors

  • Jiaqi Cai

    University of Washington

  • Eric Anderson

    University of Washington at Seattle, University of Washington

  • Heonjoon Park

    University of Washington

  • Yinong Zhang

    University of Washington

  • Jiayi Zhu

    University of Washington

  • Xiaoyu Liu

    Univ of Washington

  • Chong Wang

    University of Washington

  • William G Holtzmann

    University of Washington

  • Chaowei Hu

    University of Washington, Seattle, University of Washington

  • Zhaoyu Liu

    University of Washington

  • Takashi Taniguchi

    Kyoto Univ, National Institute for Materials Science, Research Center for Materials Nanoarchitectonics, Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, National Institute for Materials Sciences, NIMS, International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science, International Center for Materials Nanoarchitectonics, NIMS, Japan, International Center for Materials Nanoarchitectonics, Tsukuba, National Institue for Materials Science, Kyoto University, National Institute of Materials Science, International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • Kenji Watanabe

    National Institute for Materials Science, NIMS, Research Center for Electronic and Optical Materials, National Institute for Materials Science, Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, National Institute for Material Science

  • Jiun-Haw Chu

    University of Washington, Department of Physics, University of Washington, Seattle, WA 98105

  • Ting Cao

    University of Washington

  • Liang Fu

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology, MIT

  • Wang Yao

    The University of Hong Kong

  • Cui-Zu Chang

    Pennsylvania State University, The Pennsylvania State University

  • David H Cobden

    University of Washington

  • Di Xiao

    University of Washington

  • Xiaodong Xu

    University of Washington