Infrared spectroscopy of phase transitions in the lowest Landau levels of bilayer graphene
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arXiv
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| Auteurs principaux: | , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866916474707247104 |
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| author | Russell, B. Jordan Schossler, Matheus Balgley, Jesse Kapoor, Yashika Taniguchi, T. Watanabe, K. Seidel, Alexander Barlas, Yafis Henriksen, Erik A. |
| author_facet | Russell, B. Jordan Schossler, Matheus Balgley, Jesse Kapoor, Yashika Taniguchi, T. Watanabe, K. Seidel, Alexander Barlas, Yafis Henriksen, Erik A. |
| contents | We perform infrared magneto-spectroscopy of Landau level (LL) transitions in dual-gated bilayer graphene. At $ν=4$ when the zeroth LL (octet) is filled, two resonances are observed indicating the opening of a gap. At $ν=0$ when the octet is half-filled, multiple resonances disperse non-monotonically with increasing displacement field, $D$, perpendicular to the sheet, showing a phase transition at modest displacement fields from a canted anti-ferromagnet (CAFM) to the layer-polarized state, with a gap that opens linearly in $D$. When $D=0$ and $ν$ is varied, resonances at $\pmν$ show an electron-hole asymmetry with multiple line splittings as the octet is progressively filled. The $ν=4$ data show good agreement with predictions from a mean-field Hartree-Fock calculation when accounting for multiple tight-binding terms in a four-band model of bilayer graphene. However even by incorporating a valley interaction anisotropy tuned to the CAFM ground state, only partial agreement is found at $ν=0$. Our results suggest additional physics is required to understand bilayer graphene at half-filling. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2312_02489 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Infrared spectroscopy of phase transitions in the lowest Landau levels of bilayer graphene Russell, B. Jordan Schossler, Matheus Balgley, Jesse Kapoor, Yashika Taniguchi, T. Watanabe, K. Seidel, Alexander Barlas, Yafis Henriksen, Erik A. Mesoscale and Nanoscale Physics Strongly Correlated Electrons We perform infrared magneto-spectroscopy of Landau level (LL) transitions in dual-gated bilayer graphene. At $ν=4$ when the zeroth LL (octet) is filled, two resonances are observed indicating the opening of a gap. At $ν=0$ when the octet is half-filled, multiple resonances disperse non-monotonically with increasing displacement field, $D$, perpendicular to the sheet, showing a phase transition at modest displacement fields from a canted anti-ferromagnet (CAFM) to the layer-polarized state, with a gap that opens linearly in $D$. When $D=0$ and $ν$ is varied, resonances at $\pmν$ show an electron-hole asymmetry with multiple line splittings as the octet is progressively filled. The $ν=4$ data show good agreement with predictions from a mean-field Hartree-Fock calculation when accounting for multiple tight-binding terms in a four-band model of bilayer graphene. However even by incorporating a valley interaction anisotropy tuned to the CAFM ground state, only partial agreement is found at $ν=0$. Our results suggest additional physics is required to understand bilayer graphene at half-filling. |
| title | Infrared spectroscopy of phase transitions in the lowest Landau levels of bilayer graphene |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2312.02489 |