Critical Behavior in Ferroelectrics from First Principles

We report first-principles-based calculations, combined with an efficient Monte Carlo technique, that undoubtedly show that $\mathrm{Pb}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_3$, one of the most important ferroelectrics to date, adopts critical behavior that strongly deviates from the classical mean-field approach while being, in fact, consistent with the 3D-random Ising universality class.

Figure 1

Log-log plots of $-T^2\frac{d\ln ⟨p⟩}{dT}{|}_{\max }$ (panel a), $-T^2\frac{d\ln ⟨p^2⟩}{dT}{|}_{\max }$ (panel b) and $-T^2\frac{d\ln ⟨p^4⟩}{dT}{|}_{\max }$ (panel c) in arbitrary units.

Figure 2

Log-log plot of (a) the maximum value of the dielectric susceptibility and (b) $⟨p(T_c)⟩$ (in arbitrary units), as a function of the supercell dimensional, $L$.