Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 33: Low-dimensional Systems - Models II

TT 33.2: Vortrag

Freitag, 30. März 2007, 10:30–10:45, H18

Chain breaks and the susceptibility of Sr₂Cu_1−xPd_xO_3+δ and other doped quasi one-dimensional antiferromagnets — •Jesko Sirker¹, Nicolas Laflorencie¹, Satoshi Fujimoto², Sebastian Eggert³, and Ian Affleck¹ — ¹Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 — ²Department of Physics, Kyoto University, Kyoto 606-8502, Japan — ³Department of Physics, University of Kaiserslautern, 67663 Kaiserlautern, Germany

We study the magnetic susceptibility of one-dimensional S=1/2 antiferromagnets containing non-magnetic impurities which cut the chain into finite segments. For the susceptibility of long anisotropic Heisenberg chain-segments with open boundaries we derive a parameter-free result at low temperatures using field theory methods and the Bethe Ansatz. The analytical result is verified by comparing with Quantum-Monte-Carlo calculations. We then show that the partitioning of the chain into finite segments can explain the Curie-like contribution observed in recent experiments on Sr₂Cu_1−xPd_xO_3+δ. Possible additional paramagnetic impurities seem to play only a minor role.