Influence of magnetic ordering on quasiparticle spectral functions; Comparison of electronic states of CeCu and CeRuGe

Kawasaki, Ikuto  ; Fujimori, Shinichi   ; Yamagami, Hiroshi; Matsuda, Tatsuma*; Onuki, Yoshichika*

The electronic state of CeCu, an archetypical heavy compound without long-range magnetic order, has been investigated by angle-resolved photoemission spectroscopy (ARPES) experiments using soft x rays. The Ce 3-4 resonant ARPES experiments have revealed the 4 partial density of states consists of a quasiparticle band near the Fermi level ( component) and an component, the latter of which is physically equivalent to the lower Hubbard band in the Hubbard model. The observed strong intensity of the component indicates that the quasiparticle band near the Fermi level is strongly renormalized by the electron correlation effect, consistent with the significantly enhanced electronic specific-heat coefficient of CeCu. We compare the present 3-4 resonant ARPES spectra of CeCu with those for CeRuGe, which has a low Kondo temperature similar to CeCu but shows a ferromagnetic order. The results of this comparison suggest that the ferromagnetic correlation in CeRuGe seems to strongly suppress the degree of renormalization for the quasiparticle band. We also showed that the intensities of both the and components for CeCu hardly depend on temperature.