▎ 摘　　要

We investigate the collective plasmon modes in the double layer of two-dimensional materials where either one or both of the layers have tilted Dirac cone. Consistent with quite generic hydrodynamic treatment, similar to double-layer graphene systems, we find two branches of plasmons. The in-phase oscillations of the two layers disperse as root q, while the out-of-phase mode disperses as q. When even one of the layers hosts tilted Dirac cone spectrum, the plasmonic kink which is a salient feature of a monolayer of tilted Dirac cone is inherited by both of these branches. In double layers composed of graphene (nontilted) and borophene (tilted), where the two layers have two different Fermi velocities, the velocity scale of plasmonic modes is set by the greater of the two. The kink always takes place when each plasmon mode crosses an energy scale omega(kink). When the two layers have different chemical potentials, there will be two such scales, and both in-phase and out-of-phase mode develop two kinks Moreover, we find that an additional linearly dispersing overdamped mode of monolayer tilted Dirac cone system survives in the double-layer system.