Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: CE: Poster Session

TT 27.64: Poster

Mittwoch, 24. März 2010, 14:00–18:00, Poster D1

Exact diagonalization studies of small spin clusters Kondo-coupled to one-dimensional tight-binding electrons — •Martin Höck and Jürgen Schnack — Universität Bielefeld, Fakultät für Physik, D-33615 Bielefeld, Germany

Magnetic molecules are envisioned to store a single bit of information in future high-density information storage devices. For such an application it is necessary to graft the molecules on a substrate so that they can be individually addressed.

Motivated by the question of how the magnetic properties of a molecule are affected by the deposition on a surface, we study Kondo-Heisenberg model systems in which simple structures of exchange-coupled spins are interacting with one-dimensional tight-binding electrons. In particular, we focus on the magnetization of the spin cluster and examine, for different geometries, its dependence on an external magnetic field at finite temperatures. The effect of additional interaction terms like a single-ion anisotropy is also investigated.

In order to calculate the relevant thermodynamic observables, we perform a numerically exact, complete diagonalization of the model Hamiltonian. As the application of this method is limited to rather small systems, it is important to analyze the influence of finite-size effects. We investigate down to which temperatures reliable results, that adequately reflect the thermodynamic limit, can be obtained and how results for finite systems can be improved by e.g. boundary condition averaging.