### Session Y27: Focus Session: Kagome Magnets

11:15 AM–2:15 PM, Friday, March 14, 2008
Morial Convention Center Room: 219

Chair: Ying Chen, National Institute of Standards and Technology

Abstract ID: BAPS.2008.MAR.Y27.4

### Abstract: Y27.00004 : Theory of the Valence-Bond-Solid Phase on the Kagome Lattice of Zn-paratacamite

11:51 AM–12:03 PM

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#### Authors:

Michael Lawler
(University of Toronto)

Lars Fritz
(Harvard University)

Yong Baek Kim
(University of Toronto)

Subir Sachdev
(Harvard University)

We present a theory of the valence-bond-solid phase discovered in a recent neutron scattering experiment [1] on Zn-paratacamite, Zn$_x$Cu$_{4-x}$(OH)$_6$Cl$_2$, at small $x$. A theory of the Neel phase also discovered in this experiment will be presented in a related contributed talk. Zn-paratacamite has been considered as an excellent model system for the kagome lattice of spin-1/2 moments with antiferromagnetic exchange interactions. We study both the classical and quantum Heisenberg models on the distorted kagome lattice appropriate for Zn-paratacamite with small x. Our theory naturally explains the emergence of the valence bond solid phase. We suggest future inelastic neutron and elastic X-ray scattering experiments that can test our predictions. [1] S.-H. Lee et al., Nature Materials, 6, 853

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2008.MAR.Y27.4