HIDDEN ORDER IN A FRUSTRATED SYSTEM - PROPERTIES OF THE HEISENBERG KAGOME ANTIFERROMAGNET

We show that the classical Heisenberg antiferromagnet on a Kagome lattice is an example of a spin nematic. By calculating the effects of thermal fluctuations around ground states, and by Monte Carlo simulations, we find entropically driven, local spin-nematic order at low temperature T with a correlation length which is divergent in the limit T --> 0. Dynamical correlations are also studied, within the harmonic approximation, in the nematically ordered states.