Nonlinear piezoelectricity: The effect of pressure on CdTe

We report the observation of nonlinear piezoelectricity under hydrostatic pressures in a semiconductor. Optical measurements were carried out on CdTe-based piezoelectric quantum wells. At 2.7 GPa the field is changed by a factor of 2, as the result of a strong variation of the piezoelectric coefficient. Such a piezoelectric effect arises because the ionic and electronic contributions to the total polarization nearly cancel, as predicted by a recent ab initio calculation. Similar effects are expected in ZnTe, ZnSe, and InAs, where this near cancellation also occurs. \textcopyright{} 1996 The American Physical Society.