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TT: Fachverband Tiefe Temperaturen

TT 62: CE: Low-dimensional Systems - Models 2

TT 62.5: Vortrag

Freitag, 18. März 2011, 11:30–11:45, HSZ 105

Spin Correlations and Excitations in Small Antiferromagnetic Clusters — •Maren Gysler, Nikolaos P. Konstantinidis, and Oliver Waldmann — Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany

The importance of understanding correlations in small spin clusters has risen in recent years with the availability of magnetic systems such as single-molecule magnets and spins attached to surfaces, which consist of a dozen or so antiferromagnetically coupled metal centers with potentially large spin lengths. Strong correlations between neighboring spins are difficult to single out when the familiar product basis or irreducible tensor operator techniques are used. An efficient way to study ground-state correlations and low-energy spectra of small clusters is the use of the valence bond basis, which defines a natural framework where strong short range correlations can directly be incorporated in the Hilbert space basis. Using the different bases we investigate the spin correlations and excitations in a number of generic spin systems, with particular emphasis on understanding the influence of the topology of the exchange couplings. Typical theoretical models would include the even and odd short chains with large spins and small wheels.