Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.49: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
Scanning Tunneling Spectroscopy studies on heavy fermion superconductors — •Stefan Ernst1, Steffen Wirth1, Hirale Jeevan1, Christoph Geibel1, Frank Steglich1, and Zachary Fisk2 — 1Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany — 2Department of Physics and Astronomy, UC Irvine, USA
Scanning Tunneling Spectroscopy (STS) is a powerful tool for mapping the local electronic density of states (DOS) of sample surfaces. Of particular interest are experiments with superconducting (SC) materials, as information about the SC energy gap can directly be obtained. The application of STS to heavy fermion (HF) superconductors might be a valuable contribution to the understanding of this class of materials. Fundamental properties such as the symmetry of the SC order parameter or excitations due to the SC pairing interaction might be revealed.
This work reports on STM measurements carried out at low temperatures and under ultra-high vacuum (UHV) conditions with the possibility of applying a magnetic field. For the materials investigated here, spectroscopic features in the order of a few hundred µeV are expected. The sufficiently high resolution of our STM, in particular with respect to energy, has been verified. Due to the short SC coherence length of HF materials, a clean tunnel junction is required to investigate the SC gap by means of STS. Methods were developed to prepare clean surfaces of single crystals in situ. Preliminary STM and STS measurements were conducted on single crystalline samples of the HF superconductors CeCoIn5, CeIrIn5, and CeCu2Si2.