Theory of plasmonic edge states in chiral bilayer systems

We analytically describe the plasmonic edge modes for an interface that involves twisted bilayer graphene (TBG) or other similar Moire van der Waals heterostructure. For this purpose, we employ a spatially homogeneous, isotropic and frequency-dependent tensor conductivity which in principle accounts electronic electrostatic interlayer couplings. predict mode dispersion relation explicitly depends on chiral response even nonretarded limit, contrast to collective bulk excitations TBG. obtain universal function of optical plasmon paramagnetic regime. This implies correspondence chiral-TBG magnetoplasmon single sheet, chirality is interpreted as effective magnetic field. The also opens up possibility nearly undamped acoustic Our results may guide future near-field nanoscopy heterostructures. In our analysis, retain long-range interaction, apply Wiener-Hopf method system integral equations scalar potentials two layers.