Mid-infrared (MIR) plasmon-phonon features of heterostructures composing of a plasmonic anisotropic two-dimensional material (A2DM) on a hexagonal boron nitride (hBN) film are analyzed. We derive the exact dispersion relations of plasmon-phonons supported by the heterostructures and demonstrate the possibility of topological transitions of these modes within the second Reststrahlen band of hBN. The topological transitions lead to enhanced local density of plasmon-phonon states, which intensifies the spontaneous emission rate, if the thickness of the hBN layer is appropriately chosen. We also investigate a lateral junction formed by A2DM/hBN and A2DM, demonstrating that one can realize asymmetric guiding, beaming, and unidirectionality of the hybrid guided modes. Our findings demonstrate potential capabilities of the A2DM/hBN heterostructures for active tunable light-matter interactions and asymmetric in-plane polariton nanophotonics in the MIR range.
Bibliographical noteFunding Information:
Authors acknowledge financial support from DPT-HAMIT and TUBITAK projects under Nos. 113E331 and 109E301, and the Russian Science Foundation (Grant No. 19-13-00332). One of the authors (E.O.) also acknowledges partial support from the Turkish Academy of Sciences.
- 2D materials
- Hexagonal boron nitride
- In-plane anisotropy