Combined study of KNbO 3 and KTaO 3 by different techniques of photoelectron and X-ray emission spectroscopy

Abstract

The new results of the experimental study of KNbO 3 and KTaO 3 by means of X-ray photoelectron spectroscopy, soft X-ray emission and X-ray fluorescence spectroscopy are presented. In particular, Nb M 4,5 spectra ( 5p,4f→ 3d 5/2,3/2 transition) have been measured over a range of near-threshold excitation energies 206.5–240.6 eV, and Ta N 3 spectra ( 5d,6s→ 4p 3/2 transition) 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 Kα X-ray emission spectra in both compounds as well as the valence-band photoelectron spectra are brought to the binding energy scale and discussed in combination. The trends in the spectra are explained on the basis of first-principles band-structure calculations, with the dipole transition matrix elements taken into account.