We have studied the electronic structure of the skutterudite compounds CoSb3 and Co(Sb0.96Te0.04)3 by photoemission spectroscopy. Valence-band spectra revealed that a significant amount Sb 5p states are present near the Fermi level and are hybridized with Co 3d states just below it. The spectra are well reproduced by the band-structure calculation, suggesting that the effect of electron correlations is not important. When Te is substituted for Sb and n-type carriers are doped into CoSb3, the spectra are shifted to higher binding energies as described by the rigid-band model. From this shift and the free-electron model for the conduction and valence bands, we have estimated the band gap of CoSb3 to be 0.03-0.04eV, consistent with transport measurements. Photoemission spectra of RhSb3 have also been measured and revealed expected similarities to and differences from those of CoSb3. Unusual temperature dependence has been observed for the spectra of CoSb 3 and RhSb3 in the vicinity of the Fermi level.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)