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DS: Fachverband Dünne Schichten
DS 33: New Twists for Nanoquakes on a Chip - Emerging Applications of Surface Acoustic Waves in Condensed Matter Physics (Focussed Session): Session II
DS 33.2: Vortrag
Donnerstag, 15. März 2018, 15:15–15:30, H 2032
Acoustically-driven surface phonon-plasmon polaritons in graphene/h-BN and graphene/h-BN/graphene heterostructures on piezoelectric substrates — •Rajveer Fandan1, Jorge Pedrós1, Jürgen Schiefele2, Alberto Boscá1, Javier Martínez1, and Fernando Calle1 — 1Instituto de Sistemas Optoelectrónicos y Microtecnología, Universidad Politécnica de Madrid, Spain — 2Instituto de Ciencia de Materiales de Madrid, CSIC, Spain
Surface plasmon polaritons (SPPs) in graphene couple strongly to surface optical (SO) phonons in the substrate leading to hybridized surface phonon-plasmon polaritons (SPPPs). Moreover, unlike conventional SPPs in metals, graphene SPPPs can be tuned in situ through the modulation of the carrier density by electrostatic gating, covering the mid-IR to THz range. Here we demonstrate that surface acoustic wave (SAW) can be used to generate propagating SPPPs in graphene/h-BN and graphene/h-BN/graphene heterostructures on AlN substrates over a broad energy range. h-BN between the graphene and the AlN substrate not only significantly changes the SPPP dispersion but also enhances the lifetime as compared to the previously studied graphene/AlN system[1]. The SPP dispersion of graphene splits into multiple branches due to the coupling with the SO phonons of both h-BN and AlN. In addition, hyperbolic phonon branches appear in the case of multilayer h-BN. Moreover, the addition of a second graphene layer is shown to further disperse and strengthen the SPPPs, providing greater robustness and tunability for future SAW-based plasmonic devices. [1] Schiefele et al., Phys. Rev. Lett. 111, 237405 (2013)