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

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