Direct visualization of gate-tunable flat bands in twisted double bilayer graphene
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arXiv
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| Autores principales: | , , , , , , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| Materias: | |
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| author | Sasmal, Souvik Muzzio, Ryan Khalifa, Ahmed Majchrzak, Paulina Jones, Alfred J. H. Kao, I-Hsuan Watanabe, Kenji Taniguchi, Takashi Singh, Simranjeet Rotenberg, Eli Bostwick, Aaron Jozwiak, Chris Ulstrup, Søren Chatterjee, Shubhayu Katoch, Jyoti |
| author_facet | Sasmal, Souvik Muzzio, Ryan Khalifa, Ahmed Majchrzak, Paulina Jones, Alfred J. H. Kao, I-Hsuan Watanabe, Kenji Taniguchi, Takashi Singh, Simranjeet Rotenberg, Eli Bostwick, Aaron Jozwiak, Chris Ulstrup, Søren Chatterjee, Shubhayu Katoch, Jyoti |
| contents | The symmetry-broken correlated states in twisted double bilayer graphene (TDBG) can be tuned via several external knobs, including twist angle, displacement field, and carrier density. However, a direct, momentum-resolved characterization of how these parameters reshape the flat-band structure remains limited. In this study, we employ micro focused angle-resolved photoemission spectroscopy to investigate the flat-band dispersion of TDBG at a twist angle of 1.6, systematically varying the displacement field and carrier density via electrostatic gating. We directly observe multiple flat moir'e minibands near charge neutrality, including a flat remote valence band residing below the low-energy flat-band manifold. Furthermore, the dominant Coulomb repulsive energy over the flat- band bandwidth suggests favorable conditions for the emergence of interaction-driven correlated phenomena in TDBG. These findings establish that the formation and evolution of flat bands in TDBG arises from the interplay between the electron filling and the displacement field. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2510_19632 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Direct visualization of gate-tunable flat bands in twisted double bilayer graphene Sasmal, Souvik Muzzio, Ryan Khalifa, Ahmed Majchrzak, Paulina Jones, Alfred J. H. Kao, I-Hsuan Watanabe, Kenji Taniguchi, Takashi Singh, Simranjeet Rotenberg, Eli Bostwick, Aaron Jozwiak, Chris Ulstrup, Søren Chatterjee, Shubhayu Katoch, Jyoti Mesoscale and Nanoscale Physics Strongly Correlated Electrons The symmetry-broken correlated states in twisted double bilayer graphene (TDBG) can be tuned via several external knobs, including twist angle, displacement field, and carrier density. However, a direct, momentum-resolved characterization of how these parameters reshape the flat-band structure remains limited. In this study, we employ micro focused angle-resolved photoemission spectroscopy to investigate the flat-band dispersion of TDBG at a twist angle of 1.6, systematically varying the displacement field and carrier density via electrostatic gating. We directly observe multiple flat moir'e minibands near charge neutrality, including a flat remote valence band residing below the low-energy flat-band manifold. Furthermore, the dominant Coulomb repulsive energy over the flat- band bandwidth suggests favorable conditions for the emergence of interaction-driven correlated phenomena in TDBG. These findings establish that the formation and evolution of flat bands in TDBG arises from the interplay between the electron filling and the displacement field. |
| title | Direct visualization of gate-tunable flat bands in twisted double bilayer graphene |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2510.19632 |