Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 10: Poster: Multiferroics (with MA, DF, KR, DS)

KR 10.7: Poster

Dienstag, 23. März 2010, 10:45–13:45, Poster A

Accuracy of the DMRG method applied to the antiferromagnetic Heisenberg icosidodecahedron — •Jörg Ummethum and Jürgen Schnack — Universität Bielefeld, Fakultät für Physik, Postfach 100131, D-33501 Bielefeld

Geometrically frustrated spin systems show a variety of fascinating properties like magnetization jumps or an enhanced magnetocaloric effect. There are many methods to study such systems like exact diagonalization, quantum Monte Carlo, or DMRG. Exact diagonalization is limited to rather small systems and quantum Monte Carlo suffers from the so-called negative sign problem. The DMRG method [1] is in principle free of such limitations but the accuracy is rather limited for systems with more than one dimension.

We present results of our DMRG studies of the antiferromagnetic Heisenberg icosidodecahedron and focus on the lowest energy levels in subspaces of total magnetic quantum number which form so-called rotational bands for many antiferromagnetic spin systems [2]. The accuracy of the results and possibilities to improve it, like different orderings of the spins, are discussed.

[1] S. R. White, Phys. Rev. B 48, 10345 (1993)

[2] J. Schnack and M. Luban, Phys. Rev. B 63, 014418 (2000)