Phonon-induced wake potential in a graphene-HBN-graphene heterostructure
Year: 2026
Type: conference-abstract
Abstract: In our previous publications (Despoja et al. 2019, Kalinić et al. 2021 and 2024), we studied the wake effect in a sandwich-like structure consisting of two doped graphene sheets, separated by an insulating layer (Al2O3, SiO2, and HfO2), which is induced by an external charged particle moving parallel to the mentioned structure. In all those publications, we considered only isotropic insulators between two graphene sheets. We also assumed a zero gap between graphene and insulator to simplify calculations. In this work, we investigate for the first time the wake effect generated by an external charged particle moving parallel to the heterostructure composed by two graphene layers separated by an insulating slab that exhibits anisotropy of a uniaxial crystal. We choose an anisotropic layer of hexagonal boron nitride (hBN) because van der Waals heterostructures based on graphene and hBN layers with different stacking modes currently attract a great deal of interest owing to their potential applications (Kalinić et al. 2026, Song et al. 2026 and Wang et al. 2026). We evaluate the wake potential (the total potential in the plane of the upper graphene sheet) for a charged particle moving at the sub-threshold speed for the wake effect in a single, free graphene. The response function of each graphene is obtained using the dynamic polarization function of doped graphene within the random phase approximation for its π electrons described as Dirac’s fermions (Allison et al. 2009). The response of the anisotropic hBN layer is described by a diagonal dielectric tensor consisting of the in-plane and out-of-plane components (Caldwell et al. 2014). The first objective is to explore the effects of anisotropy of hBN on the wake potential in a graphene-insulator-graphene composite system. In particular, we examine the plasmon-phonon hybridization in the range of frequencies corresponding to the Reststrahlen bands of hBN, where the phonon modes of this material exhibit hyperbolic dispersion. We compare the results for the wake potential in the cases of the anisotropic and fictitious isotropic (with the dielectric functions equal to the in-plane or out-of-plane components) hBN layers. The second objective is to explore the effects of the graphene-insulator distance on the wake potential in a graphene-hBN-graphene nanostructure. The results for the wake potential are compared in the cases of the zero and non-zero gaps between graphene and hBN surface.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7204673919