Nonexponential relaxation in fully frustrated models

We study the dynamical properties of the fully frustrated Ising model. Due to the absence of disorder the model, contrary to spin glass, does not exhibit any Griffiths phase, which has been associated to nonexponential relaxation dynamics. Nevertheless, we find numerically that the model exhibits a stretched exponential behavior below a temperature Tp corresponding to the percolation transition of the Kasteleyn-Fortuin clusters. We have also found that the critical behavior of these clusters for a fully frustrated q-state spin model at the percolation threshold is strongly affected by frustration. In fact while in the absence of frustration the q=1 limit gives random percolation, in the presence of frustration the critical behavior is in the same universality class of the ferromagnetic q=1/2-state Potts model.