Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 97: Scanning probe techniques: Method development II
O 97.9: Vortrag
Donnerstag, 15. März 2018, 17:15–17:30, MA 005
Unexpected lateral contrast in Topografiner imaging on sub-Angström corrugations — •Gabriele Bertolini1, Robin Pröbsting1, Danilo Andrea Zanin1, Hugo Cabrera1, Urs Ramsperger1, Danilo Pescia1, and Oguzhan Gürlü1,2 — 1Laboratory for Solid State Physics, ETH Zurich, 8093 Zurich, Switzerland — 2Istanbul Technical University, Department of Physics, 34469 Istanbul, Turkey
By running the Scanning Tunnelling Microscope (STM) in the Fowler-Nordheim regime, i.e. going back to Topografiner from STM, we were able to attain lateral resolution with several nanometers on structures embedded in W(110) terraces, which have less than 20 pm corrugation. Our results showed that local work function on the surface is modified at the atomic level due to contaminants as expected, and this is reflected in the imaging capability of Topografiner with such unexpected lateral resolution. The secondary electron (SE) images and absorbed current images present complementary information. This in itself showed the extreme sensitivity of this imaging technique to local chemical environment. Furthermore our results showed that SEs dominate the signal reaching to the detector from the tip-sample junction rather than elastically back scattered electrons.