Regensburg 2019 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 6: Focus: Advanced TEM spectroscopy - low energy excitations and chemical composition at high resolution (joint session KFM/HL)
KFM 6.9: Talk
Monday, April 1, 2019, 18:20–18:40, PHY 5.0.20
Plasmonics in topological insulators — •Johannes Schultz1, Axel Lubk1, Flavio Nogueira2, Darius Pohl3, and Bernd Büchner1 — 1IFF, IFW Dresden, Helmholtzstraße 20, 01069 Dresden — 2ITF, IFW Dresden, Helmholtzstraße 20, 01069 Dresden — 3Dresden Center for Nanoanalysis, TU Dresden, 01062 Dresden
Surface plasmons are self-sustaining resonances occuring at interfaces between media whose permittivities have a different sign. They are associated with strongly enhanced, localized electrical fields, which may be coupled to external optical excitations. Surface plasmons can be used for the sub-wavelength control of electromagnetic fields. Based on this, novel electronic devices can be realized, for instance on-chip light spectrometers and linear accelerators, plasmonic rectennas for the harvesting of light or LEDs and photovoltaics with a higher efficiency. We study the properties of these surface plasmons when they are localized on a surface of a topological insulator like Bismuth selenide.
Surfaces of topological insulators contain conducting states which leads to negative permittivity on the surface and positive permittivity in the bulk. Consequently topological insulators can in principle sustain surface plasmons if they are embedded in a dielectric environment with positive permittivity. To characterize this localized surface plasmon-modes on the surfaces of topological insulators we use low loss spectroscopy techniques in the TEM.