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TT: Fachverband Tiefe Temperaturen

TT 55: Topology and Symmetry Protected Materials (joint session O/TT)

TT 55.5: Talk

Wednesday, March 20, 2024, 16:00–16:15, HL 001

Plasmonic Hot carrier Injection from Single Gold Nanoparticles into Topological Insulator (Bi2Se3) Nanoribbons — Christian Nweze¹, Tomke Eva Glier¹, •Mika Rerrer¹, Sarah Scheitz¹, Yalan Huang², Robert Zierold², Robert Blick², Wolfgang Parak², Nils Huse², and Michael Rübhausen¹ — ¹Institut für Nanostruktur- und Festkörperphysik, Centre for Free Electron Laser Science (CFEL), Universität Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany — ²Institut für Nanostruktur- und Festkörperphysik, Centre for Hybrid Nanostructures (CHyN), Universität Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany

Plasmonic gold nanoparticles (AuNP) injecting hot carriers (HC) into the topological insulator (TI) are studied with sub-micron spatially resolved Raman spectroscopy. We study the impact of single AuNP with sizes between 40 nm–140 nm on the topological surface states of single nanoribbons. In resonance at 633 nm excitation wavelength, we find phonon renormalization in the E_g²- and A_1g²- modes that we attribute to plasmonic hot carrier injection filling the Dirac cone of the Bi2Se3 TI. The phonon modes are enhanced by a factor of 350 when tuning the excitation wavelengths into interband transition of the Bi2Se3 TI and in resonance with the localized surface plasmon of AuNP. AuNP size-dependent Raman studies show strongest HC injection for particles with a size of 108 nm in agreement with the resonance energy of the localized surface plasmons in AuNP. HC injection opens the opportunity to locally manipulate the electronic properties of the TI.

Keywords: Surface-enhanced Raman Spectroscopy; Electron-Phonon coupling; Hot Carrier Injection; Plasmonics; Nanoribbons