Abstract
The electronic structures of and single crystals are investigated using a first-principles density-of-states (DOS) calculation, ultraviolet photoelectron spectroscopy (UPS), and electrolyte electroreflectance (EER). The total and partial DOS were calculated by the full-potential linearized-augmented-plane-wave method. From the calculations, the main contribution near the band edge of is determined to be dominated by the nonbonding Re d orbitals. The valence-band DOS is experimentally verified by the UPS measurements. EER measurements were performed in the energy range of 1.3–6 eV. The EER spectra exhibit sharp derivativelike structures in the vicinity of the band-edge excitonic transitions as well as higher-lying interband transitions. Transition energies are determined accurately. From the experimental and the theoretically calculated results, probable energy-band structures of and are constructed.
- Received 27 May 1999
DOI:https://doi.org/10.1103/PhysRevB.60.15766
©1999 American Physical Society