Intrinsic and extrinsic photogalvanic effects in twisted bilayer graphene
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866912783733358592 |
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| author | Peñaranda, Fernando Ochoa, Hector de Juan, Fernando |
| author_facet | Peñaranda, Fernando Ochoa, Hector de Juan, Fernando |
| contents | The chiral lattice structure of twisted bilayer graphene with D6 symmetry allows for intrinsic photogalvanic effects only at off-normal incidence, while additional extrinsic effects are known to be induced by a substrate or a gate potential. In this work, we first compute the intrinsic effects and show they reverse sign at the magic angle, revealing a band inversion at the Γ point. We next consider different extrinsic effects, showing how they can be used to track the strengths of the substrate coupling or displacement field. We also show that the approximate particle-hole symmetry implies stringent constraints on the chemical potential dependence of all photocurrents. A detailed comparison of intrinsic vs. extrinsic photocurrents therefore reveals a wealth of information about the band structure and can also serve as a benchmark to constrain the symmetry breaking patterns of correlated states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_15005 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Intrinsic and extrinsic photogalvanic effects in twisted bilayer graphene Peñaranda, Fernando Ochoa, Hector de Juan, Fernando Mesoscale and Nanoscale Physics The chiral lattice structure of twisted bilayer graphene with D6 symmetry allows for intrinsic photogalvanic effects only at off-normal incidence, while additional extrinsic effects are known to be induced by a substrate or a gate potential. In this work, we first compute the intrinsic effects and show they reverse sign at the magic angle, revealing a band inversion at the Γ point. We next consider different extrinsic effects, showing how they can be used to track the strengths of the substrate coupling or displacement field. We also show that the approximate particle-hole symmetry implies stringent constraints on the chemical potential dependence of all photocurrents. A detailed comparison of intrinsic vs. extrinsic photocurrents therefore reveals a wealth of information about the band structure and can also serve as a benchmark to constrain the symmetry breaking patterns of correlated states. |
| title | Intrinsic and extrinsic photogalvanic effects in twisted bilayer graphene |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2401.15005 |