Phase Diagram Mapping of a Moiré System Using Surface Acoustic Waves
Taking advantage of interfacial electron-phonon interactions, surface acoustic waves (SAWs) have emerged as a sensitive and contact-free technique for investigating low-dimensional materials. This noninvasive technique proves especially valuable for probing low-conductivity states and provides crucial radio-frequency conductivity information. In this work, for the first time, we extend SAW measurements to moiré systems to explore the correlated quantum phases. By fabricating twisted bilayer graphene samples within Fabry-Perot SAW resonators on Y-cut LiNbO<sub>3</sub> substrates, we demonstrate that SAWs effectively probe correlated insulating states, Landau level series, and Chern insulator phases. Our results highlight the superior sensitivity of SAWs, uncovering incompressible states inaccessible to traditional electrical transport measurements. Additionally, we observe a significant reduction in the alternating-current conductivity at half-fillings, indicative of frequency-dependent conductivity within correlated states. These findings establish SAWs as a powerful, contactless approach for probing the complex phenomena in moiré systems, including incompressible states and frequency-dependent electronic properties.
Authors
- Jinshan Yang (ORCID: https://orcid.org/0000-0002-8791-845X)
- Hua Jiang (ORCID: https://orcid.org/0000-0002-9239-8567)
- Zhongguo Zhou (ORCID: https://orcid.org/0000-0001-9009-3404)
- Faxian Xiu (ORCID: https://orcid.org/0000-0003-2860-0369)
- Takashi Taniguchi (ORCID: https://orcid.org/0000-0002-1467-3105)
- Kenji Watanabe (ORCID: https://orcid.org/0000-0003-3701-8119)
- X. C. Xie (ORCID: https://orcid.org/0000-0002-6206-0637)
- Xiangyu Cao (ORCID: https://orcid.org/0000-0003-3406-6692)
- Yicheng Mou (ORCID: https://orcid.org/0000-0002-6377-4623)
- Qian Li (ORCID: https://orcid.org/0009-0006-8464-2546)
- Cheng Zhang (ORCID: https://orcid.org/0000-0002-9882-1952)
- Shihao Zhang (ORCID: https://orcid.org/0000-0002-5787-5022)
- Haonan Chen (ORCID: https://orcid.org/0000-0002-9818-2783)
- Jingyi Yan
- Jiaming Gu (ORCID: https://orcid.org/0009-0003-4988-4193)
- Yuda Zhang
- Zehao Jia (ORCID: https://orcid.org/0009-0003-6451-3294)
- Xiaoyi Xie
- Wenjun Dai
- Chang Jiang
- Shaoming Dong
Institutions
- Hunan University (CN)
- Peking University (CN)
- National Institute for Materials Science (JP)
- Fudan University (CN)
- Center for Theoretical Physics (PL)
- Quantum (Australia) (AU)
- Quantum Devices (United States) (US)
- Science and Technology on Surface Physics and Chemistry Laboratory (CN)
- Shanghai Institute of Ceramics (CN)
- State Key Laboratory of Surface Physics
- Optica (US)
- Academia Sinica (TW)
Publication Details
- Journal
- Nano Letters
- Published
- 2025-06-06
- DOI
- https://doi.org/10.1021/acs.nanolett.5c00449
- Citations
- 1
- Primary Topic
- Underwater Acoustics Research
- Type
- article
- Field-Weighted Citation Impact
- 1.79
Funders
- National Natural Science Foundation of China
- Shanghai Education Development Foundation
- Fudan University
- Science and Technology Commission of Shanghai Municipality
- National Key Research and Development Program of China