The symmetry and density of unoccupied states of twin-free YBa2Cu3O7 and YBa2Cu4O8 single crystals have been investigated by orientation-dependent x-ray absorption spectroscopy at the O 1s edge, using a bulk-sensitive fluoresence-yield-detection method. In conjunction with earlier results obtained by electron-energy-loss spectroscopy, the relative density of unoccupied states for different oxygen sites has been derived. Comparison with local-density energy-band-structure calculations shows reasonable agreement with the experimental results.
ASJC Scopus subject areas
- Condensed Matter Physics