Abstract
We report a high-resolution resonant inelastic x-ray scattering study of . A number of spectral features are identified that were not clearly visible in earlier lower-resolution data. The momentum dependence of the spectral weight and the dispersion of the lowest-energy excitation across the insulating gap have been measured in detail. The temperature dependence of the spectral features was also examined. The observed charge-transfer edge shift, along with the low dispersion of the first charge-transfer excitation, are attributed to the lattice motion being coupled to the electronic system. In addition, we observe a dispersionless feature at , which is associated with a - crystal field excitation.
- Received 3 December 2007
DOI:https://doi.org/10.1103/PhysRevB.77.060501
©2008 American Physical Society