Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 56: CE: Heavy Fermions

TT 56.4: Talk

Thursday, March 17, 2011, 17:15–17:30, HSZ 105

Tracing the Kondo Lattice in YbRh₂Si₂ — •Stefan Ernst¹, Stefan Kirchner^2,1, Steffen Wirth¹, Cornelius Krellner¹, Christoph Geibel¹, Frank Steglich¹, and Gertrud Zwicknagl³ — ¹Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden — ²Max-Planck-institut für Physik Komplexer Systeme, Dresden — ³Institut für Mathematische Physik, TU Braunschweig

Heavy fermion (HF) metals are often characterized by a variety of relevant energy scales and competing interactions which may result in the emergence of novel states of condensed matter. Therefore, these materials have advanced to suitable model systems by means of which electronic correlations can be studied in detail. For a further in-depth understanding of the underlying physics, the application of local electronic probes is of major importance.

We present recent results of Scanning Tunneling Microscopy and Spectroscopy (STM/S) at low temperature conducted on the prototypical HF compound YbRh₂Si₂. The topography confirms an excellent low temperature in situ cleave of the single crystals. The hybridization of conduction and 4f electrons results in a gap-like feature in the tunneling conductance. In addition, the crystal field excitations are unambiguously reflected in our STS data and hence, bulk properties are predominatly probed. A strongly temperature-dependent peak in the tunneling conductance is attributed to a Kondo–lattice resonance.