Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances
The full optical response of twisted bilayer graphene at the neutrality point close to the magic angle within the continuum model (CM) is discussed. First, three different channels consistent with the underlying D 3 symmetry are identified, yielding the total, magnetic, and chiral response. Second,...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2023-06-01
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| Series: | Small Science |
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| Online Access: | https://doi.org/10.1002/smsc.202200080 |
| _version_ | 1797799325067116544 |
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| author | Tobias Stauber Martin Wackerl Paul Wenk Dionisios Margetis José González Guillermo Gómez-Santos John Schliemann |
| author_facet | Tobias Stauber Martin Wackerl Paul Wenk Dionisios Margetis José González Guillermo Gómez-Santos John Schliemann |
| author_sort | Tobias Stauber |
| collection | DOAJ |
| description | The full optical response of twisted bilayer graphene at the neutrality point close to the magic angle within the continuum model (CM) is discussed. First, three different channels consistent with the underlying D 3 symmetry are identified, yielding the total, magnetic, and chiral response. Second, the full optical response in the immediate vicinity of the magic angle θ m is numerically calculated, which provides a direct mapping of the CM onto an effective two‐band model. It is, further, shown that the ground state of the CM in the immediate vicinity of θ m is unstable toward transverse current fluctuations, a so‐called Condon instability. Third, due to the large counterflow, the acoustic plasmonic excitations with typical wave numbers have larger energies than the optical ones and their energy density may be largely enhanced at certain frequencies which are denominated as chiral resonances. Finally, symmetry relations for the optical response and their consequences for the chiral response are discussed. |
| first_indexed | 2024-03-13T04:17:07Z |
| format | Article |
| id | doaj.art-d3d8456b838545f6adf93d582bcbd110 |
| institution | Directory Open Access Journal |
| issn | 2688-4046 |
| language | English |
| last_indexed | 2024-03-13T04:17:07Z |
| publishDate | 2023-06-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Small Science |
| spelling | doaj.art-d3d8456b838545f6adf93d582bcbd1102023-06-21T00:42:44ZengWiley-VCHSmall Science2688-40462023-06-0136n/an/a10.1002/smsc.202200080Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral ResonancesTobias Stauber0Martin Wackerl1Paul Wenk2Dionisios Margetis3José González4Guillermo Gómez-Santos5John Schliemann6Instituto de Ciencia de Materiales de Madrid, CSIC E-28049 Madrid SpainInstitut für Theoretische Physik Universität Regensburg 93053 Regensburg GermanyInstitut für Theoretische Physik Universität Regensburg 93053 Regensburg GermanyInstitute for Physical Science and Technology Department of Mathematics Center for Scientific Computation and Mathematical Modeling University of Maryland College Park MD 20742 USAInstituto de Estructura de la Materia, CSIC E-28006 Madrid SpainDepartamento de Física de la Materia Condensada Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC) Universidad Autónoma de Madrid E-28049 Madrid SpainInstitut für Theoretische Physik Universität Regensburg 93053 Regensburg GermanyThe full optical response of twisted bilayer graphene at the neutrality point close to the magic angle within the continuum model (CM) is discussed. First, three different channels consistent with the underlying D 3 symmetry are identified, yielding the total, magnetic, and chiral response. Second, the full optical response in the immediate vicinity of the magic angle θ m is numerically calculated, which provides a direct mapping of the CM onto an effective two‐band model. It is, further, shown that the ground state of the CM in the immediate vicinity of θ m is unstable toward transverse current fluctuations, a so‐called Condon instability. Third, due to the large counterflow, the acoustic plasmonic excitations with typical wave numbers have larger energies than the optical ones and their energy density may be largely enhanced at certain frequencies which are denominated as chiral resonances. Finally, symmetry relations for the optical response and their consequences for the chiral response are discussed.https://doi.org/10.1002/smsc.202200080chiral responseoptical absorptionplasmonstwisted bilayer graphene |
| spellingShingle | Tobias Stauber Martin Wackerl Paul Wenk Dionisios Margetis José González Guillermo Gómez-Santos John Schliemann Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances Small Science chiral response optical absorption plasmons twisted bilayer graphene |
| title | Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances |
| title_full | Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances |
| title_fullStr | Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances |
| title_full_unstemmed | Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances |
| title_short | Neutral Magic‐Angle Bilayer Graphene: Condon Instability and Chiral Resonances |
| title_sort | neutral magic angle bilayer graphene condon instability and chiral resonances |
| topic | chiral response optical absorption plasmons twisted bilayer graphene |
| url | https://doi.org/10.1002/smsc.202200080 |
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