Hidden glassy behaviors in an ideal Heisenberg Kagomé antiferromagnet

Dynamics of classical Heisenberg spins Si on the Kagomé lattice has been studied. An ideal Heisenberg Kagomé antiferromagnet is known to remain disordered down to T=0 due to the macroscopic degeneracy of the ground state. However, we find that Si and their planar components si in the thermally selected coplanar nematic state behave in a qualitatively different way and especially planar spins (si) show the exotic glass-like transition in the very low temperature T∼0.003J (J: spin exchange). The glassy behaviors of si would be found to be driven by the spin-nematic fluctuations, different from ordinary spin glasses by disorders or anisotropies.