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

TL;DR

This study investigates the electronic structure of KNbO3 and KTaO3 using various spectroscopic techniques and compares experimental results with first-principles calculations to understand their spectral dependencies.

Contribution

It provides new experimental spectra of KNbO3 and KTaO3 and correlates these with theoretical calculations, highlighting excitation energy effects on spectral features.

Findings

Nb M(4,5) spectra depend on excitation energy

Ta N(3) spectra vary with excitation energy

Spectral trends explained by band-structure calculations

Abstract

The new results are presented of the experimental study of KNbO3 and KTaO3 by means of X-ray photoelectron spectroscopy, soft X-ray emission and X-ray fluorescence spectroscopy. In particular, Nb M(4,5) spectra have been measured over a range of near-threshold excitation energies 206.5 - 240.6 eV, and Ta N(3) spectra over 399.4 - 420.4 eV at the Advance Light Source in Berkeley. 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 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.