Possible evidence for the existence of the Fehrenbacher-Rice band: O K-edge XANES study on Pr1-xCaxBa2Cu3O7
X-ray absorption near edge structure (XANES), resistivity, and thermoelectric power have been measured on Pr 1 − x Ca x Ba2Cu3O7. These data reveal an intriguing electronic structure in Pr-doped cuprates. The absorption peak in XANES associated with the Fehrenbacher-Rice (FR) band has been identified. The Ca-doped holes in Pr 1 − x Ca x Ba2Cu3O7 go to both the Zhang-Rice (ZR) and FR bands. Comparative studies on the related samples suggest that the FR band is partially filled and highly localized. Implications of these results on other recent experiments, such as the observation of superconductivity in PrBa2Cu3O7 single crystals, are discussed.