Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 63: Posters: Scanning Probe Methods

O 63.21: Poster

Mittwoch, 2. April 2014, 17:30–21:00, P2

A combined LT-STM/FIM for tip specific tunnelling experiments — •Ben Wortmann, Matthias Müller, 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. The tip can be characterised without transfer to a different position in the UHV system, so that the probability for the modification of the tip can be strongly reduced. Ideally the tip remains unchanged. The geometry of the microscope resembles a cylinder with a height of 13 cm and a diameter of 4 cm. The STM is screwed directly onto a commercially available continuous flow cryostat which allows cooling to about 5-7 K. The very compact design minimises helium consumption to about 1 litre/hour. Insulation from vibration is provided by a combination of springs and eddy current damping. Shutters at the bottom of the microscope can be opened to expose the tip to a channel plate or closed to assure lower temperatures and minimal thermal drift while tunnelling. A combination of two piezos is used to move a magnetically attached slider holding the tip. The slider can be easily exchanged in vacuum. The performance of the STM setup has already been shown for an almost identical system [1]. [1] (H. Karacuban, M. Lange, J. Schaffert, O. Weingart, Th. Wagner and R. Möller, Surf. Sci. Lett., 603, Issue 5, L39 (2009).