Photoemission study of pyrochlore superconductor Cd₂Re₂O₇

We report photoemission study of the pyrochlore superconductor Cd₂Re₂O₇. The valence-band spectra show the Re 5d dominant band close to the Fermi level (E_F), consistent with the recent band calculations. Temperature-dependent study of the Re 5d band reveals a gradual change in spectral shape, as is seen from a gradual modification of difference spectra below 200 K. These results are related to another transition at 200 K reported from resistivity and susceptibility measurements and indicate that the transition involves a change in electronic structures of the Re 5d band near E_F.