Second-harmonic generation and origin of polar configuration in KTaO3:Li

Abstract

Results are presented for the second-harmonic generation of light in K1-xLixTaO3 for x=1.6%, 2.6%, 3.4%, and 6%. From the second-harmonic efficiency and from birefringence results, it is concluded that below the freezing temperature Tf, KTaO3:Li polar displacements are correlated over distances <d, which increase continuously with dopant concentration x from 6 nm at x=1.6% to 23 nm at x=6%. Below Tf, <d is nearly independent of T. Quadrupolar distortions are correlated over much larger distances, comparable to the wavelength of light. © 1991 The American Physical Society.