Polar Crystals

A novel conception of piezoelectricity physical nature is proposed and dicussed. Some peculiarities of piezoelectric crystals (so cold polar-neutral crystals) would be described by a assumption of their intrinsic (latent) polarity. Its components show a critical law P ~ ( - T)^n and vanish at the phase transition temperature . The critical parameter equals to n = 1 if all components of intrinsic polarity are flatness arranged (two-dimen- sional case, 2D). For spatial (3D) arrangement of the latent polarity components this exponent is n = 2. These differ essentially from 1D ferroelectric spontaneous polarization that shows P(T) critical law with the n = 0.5. For technical application, it means that under the anisotropy of boundary conditions any high-gap III-V semiconductor-piezoelectric shows a behavior of pyroelectric crystal. Such crystals might be used as far infrared sensor or as a piezoelectric sensor integrated with amplifier in one III-V crystal.