NONLINEAR PIEZOELECTRICITY - THE EFFECT OF PRESSURE ON CDTE

We report the observation of nonlinear piezoelectricity under hydrosta tic pressures in a semiconductor. Optical measurements were carried ou t on CdTe-based piezoelectric quantum wells. At 2.7 GPa the field is c hanged by a factor of 2, as the result of a strong variation of the pi ezoelectric coefficient. Such a piezoelectric effect arises because th e ionic and electronic contributions to the total polarization nearly cancel, as predicted by a recent ab initio calculation. Similar effect s are expected in ZnTe, ZnSe, and InAs, where this near cancellation a lso occurs.