High-pressure X-ray near-edge absorption measurements have been performed on thallium rhenium oxide (TlReO4) up to 10.86 GPa at room temperature and in a diamond-anvil cell. At ∼10 GPa, TlReO4 undergoes a large volume collapse and a striking optical transition, changing from transparent to opaque. A model has been proposed by Jayaraman et al. that the high-pressure phase transition is associated with a charge transfer from the thallium to rhenium atom; Tl1+(Re7+O4) -1 → Tl3+(Re5+O4)-3 and an accompanying truly octahedral coordination of the rhenium atom with respect to the surrounding oxygen cage. In this article, we find a significant broadening of ∼1.5 eV of the white-line feature at the rhenium L 3(2p3/2 → 5d) absorption-edge above this transition, and no evidence for the proposed valence change.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Thallium rhenium oxide
- X-ray absorption