Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 47: Spincaloric Transport I (jointly with TT)
MA 47.2: Talk
Thursday, April 3, 2014, 17:00–17:15, HSZ 403
Cooling nanodevices via spin-polarized currents — •Jochen Brüggemann1, Stephan Weiss2, Peter Nalbach1, and Michael Thorwart1 — 11. Institut für theoretische Physik, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg — 2Theoretische Physik, Universität Duisburg-Essen & CENICE, 47048 Duisburg
We investigate a non-equilibrium cooling scheme for nanodevices utilizing spin-polarized currents inspired by the demagnetization cooling for macroscopic systems. A minimal model is employed including the following parts: First, a quantum dot coupled to ferromagnetic leads via electron tunneling, second, a localized magnetic moment on the dot interacting with the electron spins via exchange interaction and, finally, a single phonon mode coupled to both electric and spin degrees of freedom. By deriving and solving a quantum master equation for the reduced density matrix in the sequential tunneling limit, we are able to determine both spin and phonon dynamics. Due to the combination of spin-polarized currents and spin-phonon interaction we achieve an increase of the ground state population of the localized moment and thus, subsequently, of the phonon mode compared to its initial preparation.