EFFECT OF HOLE DOPING ON THE ELECTRONIC-STRUCTURE OF ND1-XSRXTIO3

Photoelectron spectroscopy has been employed to follow the development of the electronic structure in Nd1-xSrxTiO3 as a function of x. Reson ant effects at the Ti 3p threshold were used to highlight Ti 3d contri butions in the valence bands. Particular attention is focused on Ti 3d intensity within similar to 3 eV of the Fermi level(E(F)) The total i ntensity in this region is found to correlate linearly with compositio n, as expected. Changes in the shape of this spectral structure are di scussed in terms of the one-electron spectral function. For x<0.25 (in sulating or semiconducting compositions), only incoherent intensity as sociated with the lower Hubbard band is present, Additional intensity, attributed to a coherent quasiparticle contribution, appears at the c omposition of the metal-insulator transition x similar to 0.25. The re lative intensities of these two components are determined as a functio n of x. Ti 3d intensity also occurs in the higher binding-energy regio n of the predominantly O 2p band due to Ti 3d-O 2p hybridization. Comp osition-dependent changes in this region are analyzed in order to dete rmine changes in the Ti 3d-O 2p hybridization with composition and str ucture.