Physical nature of piezoelectricity

A novel conception of peizoelectricity physical nature is proposed and dicussed. Some peculiarities of piezoelectric crystals (so cold polar-neutral crystals) would be described by a concept of their intrinsic (latent) polarity. Its components show a critical law P ~ (θ - T)ⁿ and vanish at the phase transition temperature θ. The critical parameter equals to n = 1 if all components of intrinsic polarity are flatness arranged (two-dimensional 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_S(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. It is important that such a crystal might be used as far infrared sensor or as a volume-piezoeffect sensor integrated with amplifier in one III-V crystal. On the other hand, any device based on III-V semiconductor which have erroneous orietation of crystal can generate polarisational noises due to vibrations or thermal fluctuations.