Integer and fractional Chern insulators in twisted bilayer MoTe2
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arXiv
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| Autores principales: | , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| Materias: | |
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| _version_ | 1866911944670183424 |
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| author | Zeng, Yihang Xia, Zhengchao Kang, Kaifei Zhu, Jiacheng Knüppel, Patrick Vaswani, Chirag Watanabe, Kenji Taniguchi, Takashi Mak, Kin Fai Shan, Jie |
| author_facet | Zeng, Yihang Xia, Zhengchao Kang, Kaifei Zhu, Jiacheng Knüppel, Patrick Vaswani, Chirag Watanabe, Kenji Taniguchi, Takashi Mak, Kin Fai Shan, Jie |
| contents | Chern insulators, which are the lattice analogs of the quantum Hall states, can potentially manifest high-temperature topological orders at zero magnetic field to enable next-generation topological quantum devices. To date, integer Chern insulators have been experimentally demonstrated in several systems at zero magnetic field, but fractional Chern insulators have been reported only in graphene-based systems under a finite magnetic field. The emergence of semiconductor moiré materials, which support tunable topological flat bands, opens a new opportunity to realize fractional Chern insulators. Here, we report the observation of both integer and fractional Chern insulators at zero magnetic field in small-angle twisted bilayer MoTe2 by combining the local electronic compressibility and magneto-optical measurements. At hole filling factor ν=1 and 2/3, the system is incompressible and spontaneously breaks time reversal symmetry. We determine the Chern number to be 1 and 2/3 for the ν=1 and ν=2/3 gaps, respectively, from their dispersion in filling factor with applied magnetic field using the Streda formula. We further demonstrate electric-field-tuned topological phase transitions involving the Chern insulators. Our findings pave the way for demonstration of quantized fractional Hall conductance and anyonic excitation and braiding in semiconductor moiré materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2305_00973 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Integer and fractional Chern insulators in twisted bilayer MoTe2 Zeng, Yihang Xia, Zhengchao Kang, Kaifei Zhu, Jiacheng Knüppel, Patrick Vaswani, Chirag Watanabe, Kenji Taniguchi, Takashi Mak, Kin Fai Shan, Jie Mesoscale and Nanoscale Physics Chern insulators, which are the lattice analogs of the quantum Hall states, can potentially manifest high-temperature topological orders at zero magnetic field to enable next-generation topological quantum devices. To date, integer Chern insulators have been experimentally demonstrated in several systems at zero magnetic field, but fractional Chern insulators have been reported only in graphene-based systems under a finite magnetic field. The emergence of semiconductor moiré materials, which support tunable topological flat bands, opens a new opportunity to realize fractional Chern insulators. Here, we report the observation of both integer and fractional Chern insulators at zero magnetic field in small-angle twisted bilayer MoTe2 by combining the local electronic compressibility and magneto-optical measurements. At hole filling factor ν=1 and 2/3, the system is incompressible and spontaneously breaks time reversal symmetry. We determine the Chern number to be 1 and 2/3 for the ν=1 and ν=2/3 gaps, respectively, from their dispersion in filling factor with applied magnetic field using the Streda formula. We further demonstrate electric-field-tuned topological phase transitions involving the Chern insulators. Our findings pave the way for demonstration of quantized fractional Hall conductance and anyonic excitation and braiding in semiconductor moiré materials. |
| title | Integer and fractional Chern insulators in twisted bilayer MoTe2 |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2305.00973 |