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TT: Fachverband Tiefe Temperaturen

TT 93: Superconductivity: (General) Theory

TT 93.4: Vortrag

Donnerstag, 3. April 2014, 17:15–17:30, HSZ 201

Phonon-mediated pairing in the new superconductor Ta₂PdS₅: A first principles study — •Rolf Heid and Klaus-Peter Bohnen — Institut für Festkörperphysik, Karlsruher Institut für Technologie

Recently, a new layered chalcogenide superconductor Ta₂Pd_xS₅, x ≈ 1, with a T_c of 6 K was discovered and classified as a type-II s-wave superconductor [1]. The presence of the heavy 5d element Ta and the observation of a large upper critical field well above the estimated Pauli limit led to speculations of a strong influence of spin-orbit coupling on the superconducting state. A subsequent electronic-structure calculation classified this material as an anisotropic multiband metal [2]. From a comparison of the bandstructure density of states and the measured specific heat, a strong-coupling scenario with a coupling constant larger than 2 was inferred.

Here we address the question of a strong-coupling scenario for Ta₂PdS₅ within a first principles approach. We present results for the electronic bandstructure, phonon dispersion, and the phonon-mediated pairing interaction obtained via density-functional perturbation theory. We will also discuss the relevance of spin-orbit coupling for these quantities.
Y. F. Lu et al., arXiv:1308.3766
D. J. Singh, Phys. Rev. B 88, 174508 (2013)