Byung-Hee Choi | Searcharxiv

arXiv2003

Localized Character of 4f Electrons in CeRh$_x$(x=2,3) and CeNi$_x$(x=2,5)

We have measured Ce 4f spectral weights of extremely $α$-like Ce-transition metal intermetallic compounds CeRh$_x$ (x=2,3) and CeNi$_x$ (x=2,5) by using the {\it bulk-sensitive} resonant photoemission technique at the Ce $M_5$($3d_{5/2}\to4f$)-edge. Unprecedentedly high energy resolution and longer escape depth of photoemitted electron at this photon energy enabled us to distinguish the sharp Kondo resonance tails at the Fermi level, which can be well described by the Gunnarsson-Schönhammer(GS) calculation based on the Anderson Impurity Hamiltonian. On the other hand, the itinerant 4f band description shows big discrepancies, which implies that Ce 4f electrons retain localized characters even in extremely $α$-like compounds.

cond-mat.str-el↗

arXiv1999

Photoemission Study of Rare-Earth Ditelluride Compounds (ReTe_2 : Re = La, Pr, Sm, and Gd)

We studied the electronic structure of rare-earth ditelluride (ReTe_2 : Re = La, Pr, Sm, and Gd) using photoemission spectroscopy. From the x-ray photoelectron spectroscopy (XPS) study of the 3d core levels of rare-earth elements, we found that all the rare earth elements are trivalent. We have also made theoretical calculations using the Gunnarsson and Schoenhammer approximation and multiplet calculations for the rare earth elements to find that the La and Gd~3d peaks are well explained using our calculations. There is no considerable change in the line-shape of the Te~3d peaks depending on different rare earth elements. On ther other hand, valence band spectra studied with the ultraviolet photoelectron spectroscopy (UPS) show a small change in the Te p band depending on rare-earth elements. According to the UPS data, LaTe_2 has very low carrier density at the Fermi level while SmTe_2 and PrTe_2 show strongly metallic band structure effects near the Fermi level.

cond-mat.str-el↗