de Haas-van Alphen spectroscopy and fractional quantization of magnetic-breakdown orbits in moiré graphene
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arXiv
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| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2023
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| _version_ | 1866917571359408128 |
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| author | Bocarsly, Matan Uzan, Matan Roy, Indranil Grover, Sameer Xiao, Jiewen Dong, Zhiyu Labendik, Mikhail Uri, Aviram Huber, Martin E. Myasoedov, Yuri Watanabe, Kenji Taniguchi, Takashi Yan, Binghai Levitov, Leonid S. Zeldov, Eli |
| author_facet | Bocarsly, Matan Uzan, Matan Roy, Indranil Grover, Sameer Xiao, Jiewen Dong, Zhiyu Labendik, Mikhail Uri, Aviram Huber, Martin E. Myasoedov, Yuri Watanabe, Kenji Taniguchi, Takashi Yan, Binghai Levitov, Leonid S. Zeldov, Eli |
| contents | Quantum oscillations originating from the quantization of the electron cyclotron orbits provide ultrasensitive diagnostics of electron bands and interactions in novel materials. We report on the first direct-space nanoscale imaging of the thermodynamic magnetization oscillations due to the de Haas-van Alphen effect in moiré graphene. Scanning by SQUID-on-tip in Bernal bilayer graphene crystal-axis-aligned to hBN reveals abnormally large magnetization oscillations with amplitudes reaching 500 μ_B/electron in weak magnetic fields, unexpectedly low frequencies, and high sensitivity to the superlattice filling fraction. The oscillations allow us to reconstruct the complex band structure in exquisite detail, revealing narrow moiré bands with multiple overlapping Fermi surfaces separated by unusually small momentum gaps. We identify distinct sets of oscillations that violate the textbook Onsager Fermi surface sum rule, signaling formation of exotic broad-band particle-hole superposition states induced by coherent magnetic breakdown. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_20338 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | de Haas-van Alphen spectroscopy and fractional quantization of magnetic-breakdown orbits in moiré graphene Bocarsly, Matan Uzan, Matan Roy, Indranil Grover, Sameer Xiao, Jiewen Dong, Zhiyu Labendik, Mikhail Uri, Aviram Huber, Martin E. Myasoedov, Yuri Watanabe, Kenji Taniguchi, Takashi Yan, Binghai Levitov, Leonid S. Zeldov, Eli Mesoscale and Nanoscale Physics Materials Science Quantum Gases Quantum oscillations originating from the quantization of the electron cyclotron orbits provide ultrasensitive diagnostics of electron bands and interactions in novel materials. We report on the first direct-space nanoscale imaging of the thermodynamic magnetization oscillations due to the de Haas-van Alphen effect in moiré graphene. Scanning by SQUID-on-tip in Bernal bilayer graphene crystal-axis-aligned to hBN reveals abnormally large magnetization oscillations with amplitudes reaching 500 μ_B/electron in weak magnetic fields, unexpectedly low frequencies, and high sensitivity to the superlattice filling fraction. The oscillations allow us to reconstruct the complex band structure in exquisite detail, revealing narrow moiré bands with multiple overlapping Fermi surfaces separated by unusually small momentum gaps. We identify distinct sets of oscillations that violate the textbook Onsager Fermi surface sum rule, signaling formation of exotic broad-band particle-hole superposition states induced by coherent magnetic breakdown. |
| title | de Haas-van Alphen spectroscopy and fractional quantization of magnetic-breakdown orbits in moiré graphene |
| topic | Mesoscale and Nanoscale Physics Materials Science Quantum Gases |
| url | https://arxiv.org/abs/2310.20338 |