Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 10: Poster Session: Superconductivity
TT 10.55: Poster
Montag, 14. März 2011, 14:00–18:00, P4
Spin-dependent boundary conditions for diffusive quasiclassical Green’s functions at weakly polarised tunnel interfaces — •Peter Machon1, Matthias Eschrig1,2, and Wolfgang Belzig1 — 1Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — 2Department of Physics, Royal Holloway, University of London, Egham Hill, EGHAM, TW20 0EX, UK
The quasiclassical Green’s function method is a standard tool to describe the transport properties of diffusive superconducting heterostructures. Since this approach is not suited for heterostructures containing ferromagnets it has to be supplemented by spin-dependent boundary conditions [1]. Here we present a correction to the boundary conditions [1] for the case of weakly polarized tunnel interfaces. The resulting matrix current is described by a few parameters containing the spin-dependent interfacial phase shifts. We apply the new boundary conditions to a three terminal proximity system using a finite-element approach to study the influence of these parameters on the conductivities. Our setup consists of two ferromagnetic and a superconducting terminal coupled via tunneling barriers. We analyze the local and nonlocal spin-dependent currents and determine various ways to tune the resulting conductivities using the spin-dependent interface parameters.
A. Cottet et al., Phys. Rev. B 80, 184511 (2009)