Electronic structure of La1-xPrxCoO3 and NdCoO3 studied by photoemission spectroscopy

We have investigated the electronic structure of La1-xPrxCoO3 and NdCoO3 studied by photoemission spectroscopy at 200K using several photon energies over the Pr or Nd 4d-4f resonance. All the spectra except near the 4d-4f on-resonance displayed a distinct sharp peak at due to the Co 3d6 low-spin (LS) and/or intermediate-spin (IS) state. This 1-eV peak in PrCoO3 and NdCoO3 was substantially narrower than that of LaCoO3, indicating that the IS-LS mixed state is realized in LaCoO3 at 200K while the pure LS state persists in the others. We point out that the line shape of the Pr 4f partial density of states (PDOS) of PrCoO3, extracted from the on- and off-resonance spectra, was quite different from that of PrMnO3 but rather similar to that of PrBa2Cu3O7.