Quantum oscillations in a dipolar excitonic insulator
Quantum oscillations in magnetization or resistivity are a defining feature of metals in a magnetic field. The phenomenon is generally not expected in insulators without a Fermi surface. Its observation in Kondo and other correlated insulators provided counterexamples and remains poorly understood. Here we report the observation of resistivity oscillations in a gate-controlled excitonic insulator realized in Coulomb-coupled electron-hole double layers. When the electron or hole cyclotron energy is tuned to exceed the exciton binding energy, recurring transitions arise between the excitonic insulator and layer-decoupled quantum Hall states. Compressibility measurements show an oscillatory exciton binding energy as a function of the magnetic field and electron-hole pair density. Coulomb drag measurements further reveal the signature of finite-angular-momentum excitonic correlations. These findings are qualitatively captured by mean-field calculations. Our study establishes a highly tunable platform based on electron-hole double layers for studying quantum oscillations in correlated insulators.
Authors
- Kin Fai Mak (ORCID: https://orcid.org/0000-0002-5768-199X)
- Raghav Chaturvedi (ORCID: https://orcid.org/0000-0002-3966-8265)
- Allan H. MacDonald (ORCID: https://orcid.org/0000-0003-3561-3379)
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- Jie Shan (ORCID: https://orcid.org/0000-0003-1270-9386)
- Bo Zou (ORCID: https://orcid.org/0000-0003-3047-7523)
- Phuong X. Nguyen (ORCID: https://orcid.org/0000-0003-0327-4544)
Institutions
- National Institute for Materials Science (JP)
- Cornell University (US)
- Laboratoire de physique des Solides (FR)
- Max Planck Institute for the Structure and Dynamics of Matter (DE)
- The University of Texas at Austin (US)
Publication Details
- Journal
- Nature Materials
- Published
- 2025-08-25
- DOI
- https://doi.org/10.1038/s41563-025-02334-3
- Citations
- 5
- Primary Topic
- Quantum and electron transport phenomena
- Type
- article
- Field-Weighted Citation Impact
- 6.23
Funders
- National Science Foundation
- U.S. Department of Energy
- National High Magnetic Field Laboratory
- Ministry of Education, Culture, Sports, Science and Technology
- Max-Planck-Gesellschaft
- Office of Science
- Kavli Institute at Cornell, Cornell University
- Division of Materials Research
- Basic Energy Sciences
- Core Research for Evolutional Science and Technology
- High Magnetic Field Laboratory, Chinese Academy of Sciences