Electronic structure of layered ferroelectric high-k titanate La2Ti2O7

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 alpha(Ti) = 872.4 and alpha(O) = 1042.3 eV. Chemical bonding effects have been discussed with binding energy (BE) differences Delta(Ti) = (BE O 1s - BE Ti 2p(3/2)) = 71.6 eV and Delta(La) = (BE La 3d(5/2) - BE O 1s) = 304.7 eV as key parameters in comparison with those in several titanium- and lanthanum-bearing oxides.