# Magnetic susceptibility and specific heat of the spin-1/2 Heisenberg model on the kagome lattice and experimental data on ZnCu3(OH)6Cl2

## TL;DR

This study calculates magnetic susceptibility and specific heat of the spin-1/2 kagome Heisenberg model using high-temperature expansions and exact diagonalizations, comparing results with experimental data on ZnCu3(OH)6Cl2 to understand its magnetic properties.

## Contribution

It provides a detailed comparison between theoretical calculations and experimental data, revealing the limitations of the pure kagome Heisenberg model in explaining low-temperature behavior.

## Key findings

- Accurate reproduction of susceptibility down to k_BT/J~0.2
- Estimated exchange interaction J~190K
- Identified additional interactions affecting low-temperature entropy

## Abstract

We compute the magnetic susceptibility and specific heat of the spin-1/2 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 k_BT/J~0.2, our calculations reproduce accurately the experimental susceptibility, with an exchange interaction J~190K 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 ~20K) is smaller in ZnCu3(OH)6Cl2 than in the kagome Heisenberg model, a likely signature of other interactions in the system.