Collective excitations and plasmon spectrum in twisted bilayer graphene near the magic angle

Abstract

Twisted bilayer graphene with tiny rotation angles have drawn significant attention due to the observation of the unconventional superconducting and correlated insulating behaviors. In this paper, we employ a full tight-binding model to investigate collective excitations in twisted bilayer graphene near magic angle. The polarization function is obtained from the tight-binding propagation method without diagonalization of the Hamiltonian matrix. With the atomic relaxation considered in the simulation, damped and undamped interband plasmon modes are discovered near magic angle under both room temperature and superconductivity transition temperature. In particular, an undamped plasmon mode in narrow bands can be directly probed in magic angle twisted bilayer graphene at superconductivity transition temperature. The undamped plasmon mode is tunable with angles and gradually fades away with both temperature and chemical potential. In practice, the flat bands in twisted bilayer graphene can be detected by exploring the collective plasmons from the measured energy loss function.

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Cited by in corpus (17)

• Roadmap on Nonlocality in Photonic Materials and Metamaterials
• Flat-band plasmons in twisted bilayer transition metal dichalcogenides
• Commensurate and incommensurate double moiré interference in twisted trilayer graphene
• Why the first magic-angle is different from others in twisted graphene bilayers: interlayer currents, kinetic and confinement energy and wavefunction localization
• Tunable interband and intraband plasmons in twisted double bilayer graphene
• Theory of plasmonic edge states in chiral bilayer systems
• Plasmonic Quantum Dots in Twisted Bilayer Graphene
• Tuning flat bands by interlayer interaction, spin-orbital coupling, and external fields in twisted homotrilayer MoS${}_2$
• Neutral magic-angle bilayer graphene: Condon instability and chiral resonances
• Many-body perturbation theory for moiré systems
• Theoretical determination of the effect of a screening gate on plasmon-induced superconductivity in twisted bilayer graphene
• Magnetoplasmons in magic-angle twisted bilayer graphene
• Review of the tight-binding method applicable to the properties of moiré superlattices
• Magic angle and plasmon mode engineering in twisted trilayer graphene with pressure
• Two-dimensional moiré phonon polaritons
• Disorder Suppression of Charge Density Waves in the Honeycomb Holstein Model
• Control of Plasmons in Doped Topological Insulators via Basis Atoms