DIPOLE FE3-O-I CENTER REORIENTATIONS IN INCIPIENT FERROELECTRIC KTAO3- LIGHT-INDUCED AND PHONON-INDUCED EFFECTS()

The simultaneous action of two actual mechanisms of photoinduced align ment effect (PAE) of axial electronic centers is considered. Namely, t hese mechanisms are: (i) in-center photoinduced reorientations accompa nied by photorecharging of centers and (ii) re-occupations of orientat ional states due to carrier trapping. PAE on Fe-K(3+)-O-1(2-) centers in KTaO3 is considered as an example. The value of the potential barri er between different center orientations (approximate to 0.34 eV) has been determined by linear dichroism measurements of phonon-induced reo rientation rates. Quantitative explanation of PAE temporal dependence is achieved.