Europhys. Lett.
Volume 73, Number 2, January 2006
Page(s) 271 - 277
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 09 December 2005
Europhys. Lett., 73 (2), pp. 271-277 (2006)
DOI: 10.1209/epl/i2005-10380-y

Interaction effects between impurities in low-dimensional spin- $\mth{(1/2)}$ antiferromagnets

F. Anfuso1 and S. Eggert1, 2

1  Department of Physics, Chalmers University of Technology S-412 96 Göteborg, Sweden
2  Department of Physics, University of Kaiserslautern D-67663 Kaiserslautern, Germany

received 15 September 2005; accepted in final form 18 November 2005
published online 9 December 2005

We are considering the interplay between several non-magnetic impurities in the spin-(1/2) Heisenberg antiferromagnet in chains, ladders and planes by introducing static vacancies in numerical quantum Monte Carlo simulations. The effective potential between two and more impurities is accurately determined, which gives a direct measure of the quantum correlations in the systems. Large effective interaction potentials are an indication of strong quantum correlations in the system and reflect the detailed nature of the valence bond ground states. In two-dimensions (2D) the interactions are smaller, but can still be analyzed in terms of valence bonds.

75.10.Jm - Quantized spin models.
75.30.Hx - Magnetic impurity interactions.

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