COMPOSITION DEPENDENT ELECTRONIC-STRUCTURE EFFECTS IN ND1-XSRXTIO3

The development of the electronic structure in Nd1-xSrxTiO3 as a funct ion of x was investigated using resonant photoelectron spectroscopy. A ttention is focussed indication of changes in the Ti 3d-O2p hybridizat ion and on electron-electron correlation effects evident in the Ti 3d intensity within similar to 3 eV of the Fermi level (E-F). The energet ic position of the Ti 3d intensity signals the importance of electron correlation effects. The total intensity in this region is found to co rrelate linearly with composition and changes in the spectral structur e are discussed in terms of the one-electron spectral function. For x < 0.25 (insulating or semiconducting compositions), only incoherent in tensity associated with the lower Hubbard band is present Additional i ntensity, attributed to a coherent quasiparticle contribution, appears at the composition of the metal-insulator transition, x similar to 0. 25. Ti 3d intensity also occurs in the higher binding energy region of the predominantly O 2p band due to Ti 3d O-2p hybridization. Composit ion-dependent changes in this region are analyzed to determine changes in the Ti 3d-O2p hybridization with composition and structure.