Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.112: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

A combined LT-STM/FIM for tip specific tunnelling experiments — •Ben Wortmann and Rolf Möller — Faculty of Physics, Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, 47048 Duisburg, Germany

We present details on a homebuilt, compact, low temperature scanning tunnelling microscope that allows in situ field ion microscopy of a cooled tunnelling tip inside the STM. Therefore a characterization of the tip is possible without transfer to a different position in the UHV system. This guarantees that the tip characterized by FIM is identical to the one used for the STM experiment. The geometry of the microscope resembles a cylinder with a height of only 13 cm and a diameter of 4 cm. Shutters at the bottom of the microscope can be opened to expose the tip to a channel plate or closed to assure even lower temperatures and minimal thermal drift while tunnelling. A combination of two piezo-electric accentuators is used to move a magnetically attached unit (*slider*) by a slip-stick motion. The tip is spot welded to the slider which can be easily exchanged in vacuum. The STM is screwed directly onto a commercially available continuous flow cryostat which allows cooling to about 5-7 K. Insulation from vibration is provided by a combination of springs and eddy current damping. An almost identical system already shows the performance of the STM setup[1]. The very compact design minimises helium consumption to about 1 litre/hour. [1] (H. Karacuban, M. Lange, J. Schaffert, O. Weingart, Th. Wagner and R. Möller, Surf. Sci. Lett., 603, Issue 5, L39 (2009).