Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Scanning probe methods)
O 35.4: Poster
Dienstag, 15. März 2011, 18:30–22:00, P3
A sub-Kelvin facility for cross-sectional scanning tunneling spectroscopy of metal-semiconductor heterostructures — •Peter Löptien, Focko Meier, Lihui Zhou, Jens Wiebe, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Germany
We investigate III-V semiconductors with magnetic dopants by spin-resolved scanning tunneling spectroscopy in order to achieve an atomic-scale understanding of magnetism in these systems [1, 2]. The method of choice for ex-situ grown heterostructures is cross-sectional scanning tunneling microscopy which enables to study their bulk properties by looking at nonpolar surfaces prepared by cleavage under ultra high vacuum conditions [3]. For these experiments we have planned and constructed a low-temperature scanning tunneling microscopy facility with the possibility to move the sample laterally. The main chamber being commercially available consists of a Joule-Thomson cryostat with a scanning tunneling microscope. It has a base temperature of less than 1 K using 4He. There are two additional home built vacuum chambers for in-situ sample and tip preparation. These chambers include several electron beam evaporators, a customized sample heating manipulator, an electron beam heater and a sputter gun. The whole system is attached to a frame and supported by passive air damping legs. We will show first test measurements.
[1] F. Meier et al., Science 320, 82 (2008)
[2] A. A. Khajetoorians et al., Nature 467, 1084 (2010)
[3] M. Bertelli, P. Löptien et al., Phys. Rev. B 80, 115324 (2009)