Magnetic susceptibility and specific heat of the spin- Heisenberg model on the kagome lattice and experimental data on ZnCu3(OH)6Cl2
Service de Physique Théorique, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
2 Laboratoire de Physique Théorique de la Matière Condensée, Univ. P. et M. Curie, 75252 Paris Cedex, France
Corresponding author: a email@example.com
Published online: 1 November 2007
We compute the magnetic susceptibility and specific heat of the spin- Heisenberg model on the kagome lattice with high-temperature expansions and exact diagonalizations. We compare the results with the experimental data on ZnCu3(OH)6Cl2 obtained by Helton et al. [Phys. Rev. Lett. 98, 107204 (2007)]. Down to kBT/J≃0.2, our calculations reproduce accurately the experimental susceptibility, with an exchange interaction J≃190 K and a contribution of 3.7% of weakly interacting impurity spins. The comparison between our calculations of the specific heat and the experiments indicate that the low-temperature entropy (below ~20 K) is smaller in ZnCu3(OH)6Cl2 than in the kagome Heisenberg model, a likely signature of other interactions in the system.
PACS: 75.50.Ee – Antiferromagnetics / 75.10.Jm – Quantized spin models / 75.40.Cx – Static properties
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007