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TT: Tiefe Temperaturen

TT 9: Neue und unkonventionelle Supraleiter

TT 9.3: Vortrag

Dienstag, 25. März 2003, 10:00–10:15, HSZ301

Composite Spin-Triplet Superconductivity in an SU(2)⊗ SU(2) Symmetric Lattice Model — •Frithjof Anders — Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstr.8, 64289 Darmstadt

The two-channel Anderson lattice model which has SU(2)⊗ SU(2) symmetry is of relevance to understanding of the magnetic, quadrupolar and superconducting phases in U_1−xTh_xBe₁₃ or Pr base skutterudite compounds such as PrFe₄P₁₂ or PrOs₄Sb₁₂. Possible unconventional superconducting phases of the model are explored. They are characterized by a composite order parameter comprising of a local magnetic or quadrupolar moment and a triplet conduction electron Cooper-pair. This binding of local degrees of freedom removes the entropy of the non Fermi-liquid normal state. We find superconducting transitions in the intermediate valence regime which are suppressed in the stable moment regime. The gap function is non analytic and odd in frequency: a pseudo-gap develops in the conduction electron density of states which vanishes as |ω| close to ω=0. In the strong intermediate valent regime, the gap function acquires an additional k-dependence.