Electronic structure of layered ferroelectric high-<i>k</i>titanate La₂Ti₂O₇

Abstract

The electronic structure of binary titanate La2Ti2O7 has been studied by x-ray photoelectron spectroscopy. Spectral features of valence band and all constituent element core levels have been considered. The Auger parameters of titanium and oxygen in La2Ti2O7 are determined as αTi = 872.4 and αO = 1042.3 eV. Chemical bonding effects have been discussed with binding energy (BE) differences ΔTi = (BE O 1s − BE Ti 2p3/2) = 71.6 eV and ΔLa = (BE La 3d5/2 − BE O 1s) = 304.7 eV as key parameters in comparison with those in several titanium- and lanthanum-bearing oxides.