Exact Solution of the Two-Dimensional Slater KDP Model of a Ferroelectric

Abstract

The Slater KDP model is solved for all temperatures and with an electric field. Above ${T}_{c}$ the specific heat behaves like ${(T\ensuremath{-}{T}_{c})}^{\ensuremath{-}\frac{1}{2}}$ and the polarizability like ${(T\ensuremath{-}{T}_{c})}^{\ensuremath{-}1}$. There is a first-order phase transition at ${T}_{c}$ (latent heat). Below ${T}_{c}$ the free energy is simply $\ensuremath{-}|\mathcal{E}|d$ ($\mathcal{E}=\mathrm{electric}\mathrm{field}$, $d=\mathrm{dipole}\mathrm{moment}$).