Plasmonics in topological insulators: Spin-charge separation, the influence of the inversion layer, and phonon-plasmon coupling

Abstract

We demonstrate via three examples that topological insulators (TI) offer a new platform for plasmonics. First, we show that the collective excitations of a thin slab of a TI display spin-charge separation. This gives rise to purely charge-like optical and purely spin-like acoustic plasmons, respectively. Second, we argue that the depletion layer mixes Dirac and Schrödinger electrons which can lead to novel features such as high modulation depths and interband plasmons. The analysis is based on an extension of the usual formula for optical plasmons that depends on the slab width and on the dielectric constant of the TI. Third, we discuss the coupling of the TI surface phonons to the plasmons and find strong hybridisation especially for samples with large slab widths.

arXiv comment37 pages, 7 figures

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• Chiral response of twisted bilayer graphene
• Optical Response of Finite-Thickness Ultrathin Plasmonic Films
• Magnon-Plasmon Hybridization Mediated by Spin-Orbit Interaction in Magnetic Materials
• Finite-thickness effects in plasmonic films with periodic cylindrical anisotropy
• Localized Plasmons in Topological Insulators
• Non-local quantum effects in plasmons of graphene superlattices
• Controlling surface charge and spin density oscillations by Dirac plasmon interaction in thin topological insulators
• Strong coupling between a topological insulator and a III-V heterostructure at terahertz frequency
• Surface plasmon-phonon-magnon polariton in a topological insulator-antiferromagnetic bilayer structure
• Phonon-mediated strong coupling between a three-dimensional topological insulator and a two-dimensional antiferromagnetic material
• Topological Surface-plasmon-polaritons on Corrugated Metal-dielectric Surfaces
• The anomalous spin texture as the probe for interactions in $B{i}_{2-y}S{b}_{y}S{e}_{x}T{e}_{3-x}$
• Dipolar optical plasmon in thin-film Weyl semimetals
• Tunable plasmon modes and topological transitions in single- and bilayer semi-Dirac materials
• Dynamical density response and collective modes of topological insulator ultra-thin films
• Anomalous skew scattering of plasmons in a Dirac electron fluid