Berlin 2008 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 25: Superconductivity: Heterostructures, Andreev Scattering, Proximity Effect, Coexistence

TT 25.1: Vortrag

Mittwoch, 27. Februar 2008, 14:00–14:15, H 3010

Andreev bound state spectrum in half-metallic ferromagnets — •Matthias Eschrig — Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe

Half-metallic ferromagnets are important for potential applications in spintronics and as sources of completely spin-polarized currents. In heterostructures with superconductors they introduce new effects in the interface regions, like spin-mixing and triplet rotation. A triplet supercurrent trough a half metal has been prediced [1] and experimentally verified [2]. Another interesing question regards the question how the density of states is modified in the half-metallic region. Here we present results of the Andreev bound state spectrum in a half-metal/superconductor proximity structure. We discuss the dependence on the interface parameters that enter the interface scattering matrix of the heterostructure. We discuss the role of odd-frequency pairing amplitudes in the proximity structure [3]. We also study the modification of the Andreev bound state spectrum in a superflow.

[1] M. Eschrig et al., Phys. Rev. Lett. 90, 137003 (2003).

[2] R.S. Keizer et al., Nature, 439, 825-827 (2006).

[3] M. Eschrig, T. Löfwander, submitted to Nature Physics.