NONERGODIC BEHAVIOR IN FRUSTRATED SQUARE ICE

Abstract

A frustrated vertex model is proposed to elucidate some essential properties in proton glass. The frustration mechanism is clarified which arises from the geometric constraint, the so-called ice rule, rather than competing ferroelectric and antiferroelectric interactions. By comparing two order parameters which are obtained by exact thermal averaging and by Monte Carlo sampling, broken ergodicity as well as broken symmetry is examined. Estimation of the diffusion constant in a diffusion process in relevant configuration space allows us to discuss the ergodic convergence property in connection with the free energy surface structure.