O2phole-assisted electronic processes in thePr1−xSrxMnO3(x=0.0, 0.3) system

Abstract

Experimental results, by x-ray absorption (XAS) at the oxygen K-edge and photon-energy dependence of the O 1s2p2p Auger line at the O K threshold, below Mn L-2,L-3 as well as well above the Mn L-2,L-3 edge of colossal magnetoresistance (CMR) manganites Pr1-xSrxMnO3 (PSMO) with x=0.0 and x=0.3 compositions, demonstrate the existence of an oxygen 2p hole state and show its importance in the electronic processes. Both XAS and Auger spectra self-consistently manifest that the oxygen 2p holes density of state (DOS) increases with hole doping in the PSMO system, hinting at a hole state transfer from e(g) symmetry orbitals of Mn 3d valence bands to oxygen 2p with a Mn4+ ion increase through Sr2+ doping. These are discussed in terms of the possible interatomic hybridization of Mn 3d with O 2p orbitals and a different O 2p valence band DOS for different PSMO compositions in the frame of a covalent picture.