Angle resolved oxygen K-edge x-ray absorption spectroscopy measurements were performed on single crystals of YBa2Cu3O6.9. Measurements were carried out on in situ cleaved crystals at 20 K to minimize the loss of oxygen from the surface region of the samples. It was found that there are two distinct transitions between 526 and 531 eV. The peaks in YBa2Cu3O6.9 show strong orientation dependence, as well as energy dispersion of 2 eV. After the sample is heated to room temperature, there is only one peak visible which shows little energy dispersion or orientation dependence. Comparison of the experimental results to a transition-state calculation of the absorption cross section shows good agreement indicating that there are holes of symmetry on all Cu-O bonds.
ASJC Scopus subject areas
- Condensed Matter Physics