Piezoelectric Effect as Manifestation of Polar-Sensitive Bonds in Crystals

Piezoelectrics play an important role in the microelectronic devices. To describe their electromechanical properties the phenomenological theories usually used, in particular, crystallography. Nowadays the microscopic models also can have an important value in connection with beginning applications of piezoelectrics in the nanoelectronics. Proposed model is based on asymmetry in electronic density distribution along atomic bonds, which ensures the readiness of crystal to a polar (electrical) response onto non-electrical action. It is shown that difference between piezoelectrics and other polar crystals - pyroelectrics - is not fundamental, both properties can be explained by spatial distribution of polar-sensitive (mixed ionic-covalent) bonds, emerged as a result of compensation of atoms electronegativities.