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O: Fachverband Oberflächenphysik
O 16: Scanning Probe Techniques: Method Development
O 16.6: Vortrag
Montag, 17. März 2025, 16:15–16:30, H25
STM-induced luminescence with a parabolic mirror - millions of counts — •Yannis Hilgers, Andreas Reutter, Mike Stummvoll, Markus Etzkorn, and Uta Schlickum — Institute of Applied Physics - LENA, TU Braunschweig, Germany
In recent years, scanning tunneling microscopy-induced luminescence (STML) has become a powerful technique allowing to record topography with atomic resolution and simultaneous spatially resolved photon count maps. We have built a Photon STM with a large parabolic mirror which was specifically designed for high photon collection efficiency. With this system we detected so far unreached photon counts of about 6 million photons per second at 1 nA tunnelling current that result from the decay of plasmon-polariton excitations between a Ag(111) surface and a Ag tip. Considering losses due to geometry, shadowing, optical components and detectors, we estimate a yield of approximately 5 · 10−3 photons per tunnelling electron. This is scratching on the theoretical predictions by Johansson et al. 1 , Persson and Baratoff 2 and others who all reported conversion factors in the range of 10−4 to 10−3 at most. In this talk we discuss these results, the instrumental calibrations and assumptions necessary for this estimation and speculate about possible explanations of the high observed excitation efficiency.
1 P. Johansson, R. Monreal, P. Apell - Phys. Rev. B 42, 9210 (1990)
2 B.N.J. Persson, A. Baratoff - Phys. Rev. Lett. 68, 3224 (1992)
Keywords: STM; STML; Plasmons