Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 20: Transport: Nanoelectronics I - Quantum Dots, Wires, Point Contacts - Part 2
TT 20.1: Hauptvortrag
Dienstag, 28. März 2006, 14:00–14:30, HSZ 105
Theory of inelastic scattering from magnetic impurities — •Gergely Zarand1,2, Laszlo Borda1, Natan Andrei3, and Jan von Delft4 — 1Budapest Univ. of Technology and Economics, Ungarn — 2Institut für Theoretische Festkörperphysik, Universität Karlsruhe — 3Rutgers University — 4LM Universität München
Inelastic processes play a crucial role in mesoscopic structures, where these processes destroy quantum interference effects. Recent experiments on quantum wires seem to support that much of these inelastic processes originate from magnetic impurities. Here we provide a framework that - at least at T=0 temperature - allows one to give a precise definition for the inelastic scattering rate and we show how this can be obtained for general quantum impurity models. As an example, we compute the full energy dependence of the inelastic scattering rate for the single channel Kondo problem using the non-perturbative machinery of numerical renormalization group. In contrast to naive expectations, we find a broad plateau of almost constant inelastic scattering rate for energies above the Kondo temperature, E>TK, and a quasi-linear behavior below TK, which crosses over to the expected Fermi liquid behavior, σinel(E) ∼ E2/TK only at very small energies. This behavior compares well with recent experimental observations.