A theory of piezoelectricity in zinc-blende-type and wurtzite-type crystals is given. The charge-transfer effect contributes mainly to the piezoelectric constant. The assumption of the second-nearest-neighbor electron interaction $\pi$-electronic energy) in the crystal enables us to predict theoretically the charge-transfer value, so that the piezoelectric coefficients can be calculated. The $\pi$-electronic interaction energy is found to be 0.5 ∼ 0.8 times the $\sigma$-bonding (tetrahedral-bonding) energy in wurtzite crystals.

• Received 27 January 1971

DOI:https://doi.org/10.1103/PhysRevB.5.4030