Collective excitations and plasmon spectrum in twisted bilayer graphene near the magic angle
arXiv:2010.14040 · doi:10.1103/PhysRevB.103.115431
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.
References in corpus (15)
- Flat Bands in Slightly Twisted Bilayer Graphene
- Continuum Model of the Twisted Bilayer
- Lattice relaxation and energy band modulation in twisted bilayer graphenes
- Superlattice-induced insulating states and valley-protected orbits in twisted bilayer graphene
- Numerical studies of confined states in rotated bilayers of graphene
- Modeling electronic structure and transport properties of graphene with resonant scattering centers
- Noiseless nonreciprocity in a parametric active device
- The crucial role of atomic corrugation on the flat bands and energy gaps of twisted bilayer graphene at the "magic angle"
- Continuum models for twisted bilayer graphene: the effects of lattice deformation and hopping parameter
- Effect of Point Defects on the Optical and Transport Properties of MoS2 and WS2
- Excitation spectrum and high energy plasmons in single- and multi-layer graphene
- Quasi-flat plasmonic bands in twisted bilayer graphene
- Chiral plasmons with twisted atomic bilayers
- Optical and plasmonic properties of twisted bilayer graphene: Impact of interlayer tunneling asymmetry and ground-state charge inhomogeneity
- Plasmonic nonreciprocity driven by band hybridization in moiré materials