Theory of intrinsic acoustic plasmons in twisted bilayer graphene
We present a theoretical study of the intrinsic plasmonic properties of twisted bilayer graphene (TBG) as a function of the twist angle ¿ (and other microscopic parameters such as temperature and filling factor). Our calculations, which rely on the random phase approximation, take into account four...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/427278 |
| Acceso en línea: | https://hdl.handle.net/2117/427278 https://dx.doi.org/10.1103/PhysRevB.110.045431 |
| Access Level: | acceso abierto |
| Palabra clave: | Plasmons (Physics) Graphene Electron gas Plasmons (Física) Grafè Gas d'electrons Àrees temàtiques de la UPC::Física::Física de partícules |
| Sumario: | We present a theoretical study of the intrinsic plasmonic properties of twisted bilayer graphene (TBG) as a function of the twist angle ¿ (and other microscopic parameters such as temperature and filling factor). Our calculations, which rely on the random phase approximation, take into account four crucially important effects, which are treated on equal footing: (i) the layer-pseudospin degree of freedom, (ii) spatial nonlocality of the density-density response function, (iii) crystalline local field effects, and (iv) Hartree self-consistency. We show that the plasmonic spectrum of TBG displays a smooth transition from a strongly coupled regime (at twist angles ¿¿2°), where the low-energy spectrum is dominated by a weakly dispersive intraband plasmon, to a weakly coupled regime (for twist angles ¿¿2°) where an acoustic plasmon clearly emerges. This crossover offers the possibility of realizing tunable mid-infrared subwavelength cavities, whose vacuum fluctuations may be used to manipulate the ground state of strongly correlated electron systems. |
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