SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 24: Poster Session II: Plasmonics and nanooptics II
O 24.5: Poster
Montag, 1. März 2021, 13:30–15:30, P
Vibrational Heating of a Single C60 Molecule in a Current-Carrying Plasmonic Picocavity — •Borja Cirera1, Chenfang Lin1, Shuyi Liu1, Yair Litman2, Alaa Akkoush2, Martin Wolf1, Mariana Rossi2, and Takashi Kumagai1,3 — 1PC Department Fritz Haber Institute, Berlin, Germany — 2MPI for Structure and Dynamics of Matter, Hamburg, Germany — 3IMS, Okazaki, Japan
Vibrational heating in single-molecule junctions under non-equilibrium conditions is of fundamental importance in molecular electronics. Here we report on single-molecule thermometry of fullerene (C60) in a current-carrying plasmonic picocavity by combining tip-enhanced Raman spectroscopy (TERS) with low-temperature scanning tunneling microscopy (STM). Thanks to the exceptional sensitivity of TERS, intense Stokes and anti-Stokes Raman bands can be observed from single C60, enabling direct access to heating of individual vibrational modes. The precise gap-distance control in STM allows performing single-molecule thermometry in two distinct regimes, where the molecule is in contact with one or two electrodes (tip/surface), respectively. In both cases, optically induced heating is dominant for low bias voltages. At high bias voltages, the vibrational population is increased by injecting electrons into the LUMO of C60 in tunneling conditions. Upon contacting with both electrodes, the molecule strongly hybridizes with metallic states and vibrational pumping is dominated by inelastic electron scattering due to a much larger current density.