Regensburg 2002 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 12: Niedrigdimensionale Systeme, Magnetotransport II
TT 12.6: Vortrag
Dienstag, 12. März 2002, 16:15–16:30, H18
Magnetic field effects in energy relaxation mediated by Kondo impurities — •Georg Göppert1, Yuri M Galperin2, Boris L Altshuler1,3, and Hermann Grabert4 — 1Physics Department, Princeton University,Princeton, NJ 08544, USA — 2Department of Physics, University of Oslo, P.O. Box 1048, N-0316 Oslo, Norway — 3NEC Research Institute, 4 Independence Way, Princeton, NJ 08540, USA — 4Fakultät für Physik, Albert-Ludwigs-Universität, Hermann-Herder-Straße 3, D-79104 Freiburg, Germany
We study the energy distribution function of quasiparticles in voltage biased mesoscopic wires in presence of magnetic impurities and applied magnetic field. The system is described by a Boltzmann equation where the collision integral is determined by coupling to spin 1/2 impurities. We derive an effective coupling to a dissipative spin system which is valid well above Kondo temperature in equilibrium or for sufficiently smeared distribution functions in non–equilibrium. For low magnetic field an enhancement of energy relaxation is found whereas for larger magnetic fields the energy relaxation decreases again meeting qualitatively the experimental findings by Anthore et al. (cond-mat/0109297). This gives a strong indication that magnetic impurities are in fact responsible for the enhanced energy relaxation in copper wires.