Year: 2025
Type: article
Abstract: 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.
Source: Nature Materials
Authors: Phuong X. Nguyen, Raghav Chaturvedi, Bo Zou, Kenji Watanabe, Takashi Taniguchi, Allan H. MacDonald, Kin Fai Mak, Jie Shan
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $12,690
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, State of Florida
Awards: G1019936685, G1265980886, EXCITON CONDENSATION IN ATOMIC DOUBLE LAYERS, G3510308925, G369169853, PLANAR SYSTEMS FOR QUANTUM INFORMATION, PLANAR SYSTEMS FOR QUANTUM INFORMATION, NNCI: Cornell NanoScale Science and Technology Facility (CNF), National High Magnetic Field Laboratory Renewal 2023-2027, G742574937, G7879866177, G8152425740, G8618556185
OpenAlex ID: W4413495479