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arXiv · 0903.2884

Dzyaloshinskii-Moriya anisotropy and non-magnetic impurities in the $s = 1/2$ kagome system ZnCu_3(OH)_6Cl_2

Ioannis Rousochatzakis·Salvatore R. Manmana·Andreas M. Läuchli·Bruce Normand·Frédéric Mila
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Abstract

Motivated by recent nuclear magnetic resonance experiments on ZnCu$_3$(OH)$_6$Cl$_2$, we present an exact-diagonalization study of the combined effects of non-magnetic impurities and Dzyaloshinskii-Moriya (DM) interactions in the $s = 1/2$ kagome antiferromagnet. The local response to an applied field and correlation-matrix data reveal that the dimer freezing which occurs around each impurity for $D = 0$ persists at least up to $D/J\simeq 0.06$, where $J$ and $D$ denote respectively the exchange and DM interaction energies. The phase transition to the ($Q = 0$) semiclassical, 120$^\circ$ state favored at large $D$ takes place at $D/J\simeq 0.1$. However, the dimers next to the impurity sites remain strong up to values $D \sim J$, far above this critical point, and thus do not participate fully in the ordered state. We discuss the implications of our results for experiments on ZnCu$_3$(OH)$_6$Cl$_2$.

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Ioannis Rousochatzakis, Salvatore R. Manmana, Andreas M. Läuchli, Bruce Normand, Frédéric Mila. 2009-03-17. Dzyaloshinskii-Moriya anisotropy and non-magnetic impurities in the $s = 1/2$ kagome system ZnCu_3(OH)_6Cl_2. https://doi.org/10.1103/physrevb.79.214415

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