Investigation of the electronic structure in Eu1−xDyxTiO3 by means of soft X-ray absorption spectroscopy

The electronic structure of Eu1−xDyxTiO3 is investigated by means of soft X-ray absorption spectroscopy (XAS) near the Ti L2,3-edges. The spectrum of EuTiO3 shows a satellite structure in the high-energy side of four main peaks. The spectra analyzed by using a full-multiplet calculation and the observed features are almost reproduced by the cluster model. The satellite structure above four main peaks is due to the charge transfer (CT) from the O 2p orbital to the Ti 3d orbital. The intensity decreases with the composition of Dy. This tendency corresponds to the change of conductivity against x. This result means that the intensity of the charge transfer peak is strongly related to the conductivity in Eu1−xDyxTiO3. The charge transfer from the O 2p orbital to the Ti 3d orbital plays an important role in the conductivity in EuTiO3. According to the values of the parameters (charge transfer Δ, Coulomb interactions Udd, Udc) obtained by the theoretical calculation, EuTiO3 is an intermediate between the Mott-Hubbard-type and Charge-Transfer-type insulator.