Photoemission study of rare-earth ditelluride compounds (ReTe₂: Re = La, Pr, Sm, and Gd)

We studied the electronic structure of rare-earth ditelluride (ReTe₂: Re = La, Pr, Sm, and Gd) by using photoemission spectroscopy. From the X-ray photoelectron spectroscopy (XPS) study of the 3d core levels of the rare-earth elements, we found that all the rare-earth elements were trivalent. We also made theoretical calculations using the Gunnarsson and Schönhammer approximation and multiplet calculations for the rare-earth elements, and found that the La and Gd 3d peaks were well explained by our calculations. There was very little change in the lineshapes of the Te 3d peaks of different rare-earth elements. On the other hand, the valence band spectra studied with ultraviolet photoelectron spectroscopy (UPS) showed a slight change in the Te p band for different rare-earth elements. According to the UPS data, LaTe₂ had a very low carrier density at the Fermi level while SmTe₂ and PrTe₂ show strongly metallic characters near the Fermi level.