Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 3.3: Vortrag
Montag, 23. März 2009, 10:45–11:00, HSZ 304
Effects of Dzyaloshinskii-Moriya interactions and non-magnetic impurities on the S=1/2 Kagomé antiferromagnet — Ioannis Rousochatzakis1, •Salvatore R. Manmana1, Andreas M. Läuchli2, Bruce Normand3, and Frédéric Mila1 — 1Institute of Theoretical Physics (CTMC), EPF Lausanne, Schweiz — 2MPI-PKS, Dresden, Germany — 3Institute of Theoretical Physics, ETH Zürich, Schweiz
Motivated by recent NMR experiments[1] on ZnCu3(OH)6Cl2, we present an exact diagonalization study of the combined effect of non-magnetic impurities and Dzyaloshinskii-Moriya (DM) interactions in the S=1/2 Kagomé antiferromagnet. The magnetization response and the correlation matrix data reveal that the dimer freezing which occurs around the vacancy for D=0 [2] (D is the magnitude of the DM vectors) persists up to D/J ≃ 0.07, above which a phase transition to the (Q=0) semiclassical 120∘ state[3] takes place. Surprisingly however, the dimers next to the vacancy remain strong up to D/J ∼ 1−3, i.e. well above the critical point. Implications for ZnCu3(OH)6Cl2 will be discussed.
[1] A. Olariu, et al. , Phys. Rev. Lett. 100, 087202 (2008).
[2] S. Dommange, et al., Phys. Rev. B 68, 224416 (2003);
A. Läuchli, et al., Phys. Rev. B 76, 144113 (2007).
[3] O. Cépas, et al., Phys. Rev. B 78, 140405 (2008).
[4] S. Miyahara, et al., Phys. Rev. B 75, 184402 (2007).