Lifshitz points in uniaxial ferroelectrics.

Abstract

The critical behavior of Lifshitz points in systems with short range and uniaxial dipolar interaction is calculated. These multicritical points belong to a new universality class and may be relevant in the phase diagram of ${\mathrm{Sn}}_{2}$${\mathrm{P}}_{2}$(${\mathrm{Se}}_{\mathit{x}}$${\mathrm{S}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${)}_{6}$. A variety of combinations of spatially anisotropic critical behavior is possible. The critical effects in the elastic constants are briefly mentioned.