Systematic trends in the electronic structure parameters of the4dtransition-metal oxidesSrMO3(M=Zr,Mo, Ru, and Rh)

We investigated the electronic structures of the perovskite-type 4d transition-metal oxides SrMO 3 (M =Zr, Mo, Ru, and Rh) using their optical conductivity spectra σ(ω). The interband transitions in σ(ω) are assigned, andsome important electronic structure parameters, such as charge-transfer energy Δ p d , and crystal-field splitting 10Dq, are estimated. It is observed that Δ p d and 10D q decrease systematically with increasing the atomic number of the 4d transition metal. Compared with the case of 3d oxides, the magnitudes of Δ p d and 10Dq are larger. These behaviors can be explained by the more extended nature of the orbitals in the 4d oxides.