Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 84: Focus Session: Nanoscopic Superconducting Heterostructures
TT 84.2: Topical Talk
Thursday, March 19, 2015, 10:00–10:30, H 0104
Non-Equilibrium Effects in a Josephson Junction Coupled to a Precessing Spin — Mikael Fogelström1 and •Cecilia Holmqvist2 — 1Department of Microtechnology and Nanoscience, Chalmers University of Technology, 42196 Göteborg, Sweden — 2Department of Physics, Norwegian University of Science and Technology, 7491 Trondheim, Norway
I will discuss a theoretical study of s-wave superconductors coupled to a classical spin. When an external magnetic field is applied, the classical spin can be driven to precess with the Larmor frequency. This results in a time-dependent boundary condition for the superconducting quasiparticles, with different tunnelling amplitudes for spin-up and spin-down quasiparticles and where the precession produces spin-flip scattering processes. Andreev states develop at the interface with a non-equilibrium population which depend on how the spin is driven. The Andreev states carry a steady-state Josephson current whose current-phase relation could be used for characterising the spin. In addition to the charge transport, a spin current is also generated. This spin current will induce a torque and couple back to the dynamics of the classical spin.