The electronic structure of pyrochlore-type Tl2Ru2O7, which undergoes a metal-semiconductor transition at Tt∼120 K, has been studied by ultraviolet photoemission spectroscopy (UPS) and inverse-photoemission spectroscopy [bremsstrahlung isochromat spectroscopy (BIS)]. The temperature dependence of the UPS intensity around the Fermi level (EF), which is largely due to the Ru 4d states, reflects the transition. In the BIS spectra, changes occur across the metal-semiconductor transition not only near EF but also several eV above EF where the Ru 4d eg states and the Tl 6s states are dominant. It is therefore concluded that the transport properties across the metal-semiconductor transition in Tl2Ru2O7 are mainly determined by the Ru 4dt2g states around EF but that the changes in the Tl 6s states also make contributions to the transition.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2004 Jan 30|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics