Tunable interband and intraband plasmons in twisted double bilayer graphene
| Autor: | Atasi Chakraborty, Debasis Dutta, Amit Agarwal |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Condensed Matter - Materials Science
Condensed Matter - Strongly Correlated Electrons Strongly Correlated Electrons (cond-mat.str-el) Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter::Other Condensed Matter::Superconductivity Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Physics::Optics Condensed Matter::Strongly Correlated Electrons Condensed Matter::Mesoscopic Systems and Quantum Hall Effect |
| Popis: | Flat bands in twisted moire superlattices support a variety of topological and strongly correlated phenomena along with easily tunable electrical and optical properties. Here, we demonstrate the existence of tunable, long-lived, and flat intraband and interband terahertz plasmons in twisted double bilayer graphene. We show that the interband plasmons originate from the presence of a Van Hove singularity in the joint density of states and a finite Berry connection between the pair of bands involved. We find that the gapped interband plasmon mode has a universal dispersion, and the plasmon gap is specified by the location of the Van Hove singularity in the joint density of states. Metallic moire systems support an additional intraband plasmon mode which becomes flat in the large momentum limit because of the influence of the interband correlations. We demonstrate that the undamped and flat plasmon modes in moire systems are highly tunable and can be controlled by varying the vertical electric field and electron doping, and they persist over a wide range of twist angles. 4 figures, 9 pages |
| Databáze: | OpenAIRE |
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