Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Quantum Impurities, Kondo Physics
TT 11.8: Vortrag
Dienstag, 27. März 2007, 11:30–11:45, H19
A time-dependent Numerical Renormalization Group Analysis of Single Molecule Magnets — •David Roosen1, Maarten Wegewijs2, and Walter Hofstetter1 — 1Institut für Theoretische Physik, J. W. Goethe-Universität, D-60438 Frankfurt, Germany — 2Institut für Theoretische Physik A, RWTH Aachen, D-52056 Aachen, Germany
It has recently become possible to perform experiments where single molecule magnets (SMMs), which exhibit a large intrinsic spin, are attached to metallic leads and electronic transport is measured [1]. Motivated by this, a simple quantum impurity model describing SMMs was studied theoretically and it was found that the anisotropy energies dramatically change the Kondo effect observed in such systems, even making a complete screening of the magnetic degrees of freedom possible [2].
We have investigated the time-dependent Kondo effect in a single molecule magnet strongly coupled to metallic electrodes, with a sudden perturbation at time t=0. We use a generalization of the Numerical Renormalization Group for nonequilibrium situations [3]. Applying this method to a Kondo model with large spin S > 1/2 we systematically analyze the underscreening of the local moment and the effects of anisotropy terms on the real-time dynamics of the magnetization.
[1] H. Heersche et al. , Phys. Rev. Lett. 96, 206801 (2006)
[2] C. Romeike, M. R. Wegewijs, W. Hofstetter and H. Schoeller, Phys. Rev. Lett. 96, 196601 (2006)
[3] F. Anders and A. Schiller, Phys. Rev. Lett. 95, 196801 (2005)