Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 35: Poster Session I (Scanning probe methods)
O 35.9: Poster
Dienstag, 15. März 2011, 18:30–22:00, P3
Probing the thermal near-field of thin Fe-Layers on Au(111) by NSThM — •Ludwig Worbes1, David Hellmann1, and Achim Kittel2 — 1EHF, Fak. V, Physik, Carl von Ossietzky Universität Oldenburg, — 2Experimental Polymer Physics, Faculty of Mathematics and Physics, University of Freiburg, 79104 Freiburg
The evaporation of a few monolayers of Fe on top of Au(111) surfaces is known to produce nano-meter sized Fe-islands which are found at specific locations of the herringbone surface-reconstruction.
We investigate the thermal near field of these surfaces by Near-field Scanning Thermal Microscopy (NSThM). The NSThM developed in our group is based on a STM, featuring a tunnelling probe with an integrated miniaturized thermocouple temperature sensor located about 500nm behind the tunnelling gap. Therefore, we can measure the temperature change of the tip due to heat flux between a heated or cooled sample and the probe at distances of a few nanometres, mediated by thermal near fields [1]. Thermal near-field (evanescent) modes, exponentially decaying with distance to the surface, surround every body with a finite temperature. They are generated by thermally fluctuating charges, analogously to the electromagnetic far field described by Stefan-Boltzman law.
In our experiments, we observe characteristic distributions of the heat flux by thermal near-fields. That is an enhanced heat transfer at the edges of the Fe-islands due to edge enhancement effects, already known in the realm of visible light optics.
[1] Achim Kittel et al., Appl. Phys. Lett. 93, 193109 (2008)