Dr. Steffen Wirth
Max-Planck-Institute for Chemical Physics of Solids
Dresden, Germany

Almost thirty years after the groundbreaking development of the first Scanning Tunneling Microscope (STM) by Binning and Rohrer, STM has matured into an extremely powerful technique in Condensed Matter Physics. An introduction to STM, its strengths and shortfalls, and its relatives (like Atomic Force Microscopy) will be presented. Emphasis will be on Scanning Tunneling Spectroscopy (STS) which allows to explore the electronic properties of materials locally, i.e. on an atomic scale.

To demonstrate the vast capabilities of STM we will then review some examples out of our own research. For the manganese oxide material which arose much interest due to their so-called colossal magnetoresistive (CMR) behavior a local variation of the electronic properties with temperature has been observed [1,2]. Other materials of interest are superconductors which do not follow the standard Bardeen-Cooper-Schrieffer theory. Here we present indications from STS [3] for so-called unconventional superconductivity [4]. In addition, a brief discussion of very recent STM/STS experi-ments will focus on heavy fermion metals, a class of materials that has advanced to suitable model systems by means of which electronic interactions can be studied in detail.

[1] S. Rößler et al., Europhys. Lett. 83 (2008) 17009.

[2] S. Rößler et al., Appl. Phys. Lett. 96 (2010) 202512.

[3] S. Ernst et al., arXiv:1002.2878.

[4] S. Nair et al., Proc. Natl. Acad. Sci. USA 107 (2010) 9537.