Combined study of KNbO3 and KTaO3 by different techniques of photoelectronand X-ray emission spectroscopy

The new results of the experimental study of KNbO3 and KTaO3 by means of X- ray photoelectron spectroscopy, soft X-ray emission and X-ray fluorescence spectroscopy are presented. In particular, Nb M-4,M-5 spectra (5p, 4f --> 3 d(5/2,3/2) transition) have been measured over a range of near-threshold ex citation energies 206.5-240.6 eV, and Ta N-3 spectra (5d, 6s --> 4P(3/2) tr ansition) over 399.4-420.4 eV at the Beamline 8.0 of the Lawrence Berkeley National Laboratory's Advance Light Source. These spectra were found to be strongly dependent on the excitation energy. Moreover, the O K alpha X-ray emission spectra in both compounds as well as the valence-band photoelectro n spectra are brought to the binding energy scale and discussed in combinat ion. The trends in the spectra are explained on the basis of first-principl es band-structure calculations, with the dipole transition matrix elements taken into account. (C) 1999 Elsevier Science Ltd. All rights reserved.