Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 53: Correlated Electrons: Heavy Fermions
TT 53.9: Vortrag
Donnerstag, 14. März 2013, 11:45–12:00, H19
Optical study of archetypical valence-fluctuating Eu systems — V. Guritanu1, S. Seiro1, •J. Sichelschmidt1, N. Caroca-Canales1, T. Iizuka2, S. Kimura2, C. Geibel1, and F. Steglich1 — 1MPI Chemische Physik fester Stoffe, Dresden, Germany — 2UVSOR Facility, Institute for Molecular Science, Okazaki, Japan
We have investigated the optical conductivity of the prominent valence-fluctuating compounds EuIr2Si2 and EuNi2P2 in the infrared energy range to get new insights into the electronic properties of valence-fluctuating systems. For both compounds, we observe upon cooling the formation of a renormalized Drude response, a partial suppression of the optical conductivity below 100 meV and the appearance of a midinfrared peak at 0.15 eV for EuIr2Si2 and at 0.13 eV for EuNi2P2. Most remarkably, our results show a strong similarity with the optical spectra reported for many Ce- or Yb-based heavy-fermion metals and intermediate valence systems, although the phase diagrams and the temperature dependence of the valence differ strongly between Eu- and Ce-/Yb-systems. This suggests that the hybridization between 4f- and conduction electrons, which is responsible for the properties of Ce- and Yb-systems, plays an important role in valence-fluctuating Eu systems.