Resonant photoemission spectroscopy of the quenched superconductivity system:Y1−xPrxBa2Cu3O7−δsingle crystals

Abstract

The electronic structures of the quenched superconductivity system ${\mathrm{Y}}_{1\ensuremath{-}x}{\mathrm{Pr}}_{x}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7\ensuremath{-}\ensuremath{\delta}}$ (YPrBCO; $x=0,$ 0.4, 0.8) have been investigated by resonant photoemission spectroscopy (PES) measurements near the Pr $4\stackrel{\ensuremath{\rightarrow}}{d}4f$ absorption edge. With increasing x, PES data exhibit a binding-energy shift away from ${E}_{F}.$ The fine structures of YPrBCO $(x=0.8)$ are very similar to those of trivalent ${\mathrm{PrF}}_{3},$ providing evidence that Pr ions in YPrBCO are predominantly in Pr $3+$ states. Comparison of the PES spectra of YPrBCO with $x=0.8$ to the electronic structure for ${\mathrm{PrBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ obtained by using the local spin-density functional approximation incorporating the Coulomb correlation shows good agreement in the bandwidths and the peak positions of the Cu d and O p states.