O 1sX-ray absorption spectra of Sr₂RuO₄and SrRuO₃

Abstract

Keywords: electronic structure calculations, transition-metal oxides, X-ray absorption spectroscopyWe studied the electronic structure of the Sr 2 RuO 4 and SrRuO 3 using O 1s X-ray absorption spectroscopy (XAS). The experimental spectra were interpreted in terms of the electronic states calculated using the LMTO method. For the SrRuO 3 is presented a magnetic solution, however, for Sr 2 RuO 4 a magnetic solution is not stable. In both compounds, the Ru 4d and O 2p states are heavily mixed, especially in the valence band region, while Sr 4d band are concentrated mostly in the conduction band. This indicates that the Sr presents a more ionic character within the structure, while the Ru and O present a more covalent character within the structure. The density of states showed that the bandwidth of the Ru 4d in the SrRuO 3 is larger than in the Sr 2 RuO 4 due to the major dispersion perpendicular to the planes. In the XAS spectra, the absorption intensity shows a good indication of covalence effects. The major differences between the Sr 2 RuO 4 and SrRuO 3 concern in the e g band, where, the e g band is shifted for minor energies in the Sr 2 RuO 4 in relation to the SrRuO 3 . Also, the Sr 4d appears for smaller energy in the Sr 2 RuO 4 . m22.o01