Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 62: Superconductivity: Properties, Electronic Structure, Order Parameter

TT 62.2: Vortrag

Donnerstag, 14. März 2013, 15:15–15:30, H19

Superconducting properties of the filled skutterudite LaPt₄Ge₁₂ probed by thermal conductivity — •Heike Pfau, Ulrike Stockert, Roman Gumeniuk, Walter Schnelle, Helge Rosner, Michael Nicklas, Andreas Leithe-Jasper, Yuri Grin, and Frank Steglich — MPI for Chemical Physics of Solids, 01187 Dresden, Germany

Filled skutterudites have attracted much interest due to a remarkable variety of physical properties and ground states. Particular interest has been paid to the superconductors, which range from conventional BCS over multiband to unconventional types.

In this contribution we present results on the filled skutterudite LaPt₄Ge₁₂, which becomes superconducting below T_c = 8.3 K with a critical field of H_c2⁰ = 1.6 T. While for its Pr-counterpart an unconventional and/or a multiband coupling mechanism is discussed, NMR and photoemission measurements on the La-compound suggest conventional s-wave superconductivity. However, results on the series La_xPr_1−xPt₄Ge₁₂ indicate compatible order parameters for the two stoichiometric end-compounds. As a complementary and very sensitive probe of the order parameter, we performed temperature and field dependent thermal conductivity measurements on LaPt₄Ge₁₂ down to temperatures below 100 mK. Our results do not show a typical s-wave behaviour, but point towards a more complex gap structure, which will be discussed in the context of previous results on both, LaPt₄Ge₁₂ and PrPt₄Ge₁₂.