Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.1: Poster

Donnerstag, 17. März 2011, 10:00–13:00, P1

NRG calculations of the magnetization of Kondo impurities in an external field — •Martin Höck and Jürgen Schnack — Universität Bielefeld, Fakultät für Physik, D-33615 Bielefeld, Germany

The deposition of magnetic molecules on suitable substrates represents one possibility to solve the problem of addressing individual molecules so that they might be used for information storage or quantum computing purposes. However, the magnetic properties of the molecules, which for example determine the dependence of magnetization on temperature and applied field and which are crucial for such applications, will in general be influenced by the interaction with the substrate. The goal of our ongoing investigations is to better understand the form and extent of this effect.

In an attempt to theoretically approach the problem, we study single-impurity Kondo models in an external magnetic field whose impurity consists of several exchange-coupled spins and is supposed to represent a magnetic molecule. We then focus on the impurity magnetization and compare the behavior of the free and deposited molecule (the impurity) for each model.

In order to obtain reliable approximations for the thermodynamic limit of interest, i.e. the infinitely extended substrate, we carry out the calculations using Wilson’s Numerical Renormalization Group (NRG). NRG is by now a well established method and has been significantly improved in the last five years. As an additional benefit, it allows us to study the impurity magnetization both as function of temperature and magnetic field.