Monte Carlo studies of the ferroelectric phase transition in KDP

Abstract

The order-disorder type ferroelectric phase transition in KDP is described by the pseudospin model. Four-particle cluster approximation provides its solution which fits well with the experimental data. Here we check for the first time how this approximation is exact in the absence of proton tunneling and long-range dipole interactions by means of Monte Carlo simulations. Polarization, dielectric susceptibility and heat capacity analytical curves are reproduced well by our simulations and the difference in critical temperature turns out to be much less than a percent.