Fermi surface topology and hot spot distribution in the Kondo lattice system CeB6

Rare-earth hexaborides have attracted considerable attention recently in connection to a variety of correlated phenomena including heavy fermions, superconductivity, and low-temperature magnetic phases. Here, we present high-resolution angle-resolved photoemission spectroscopy studies of trivalent CeB₆ and divalent BaB₆ rare-earth hexaborides. We find that the Fermi surface electronic structure of CeB₆ consists of large oval-shaped pockets around the X points of the Brillouin zone, whereas the states around the zone center Γ point are strongly renormalized. Our first-principles calculations agree with our experimental results around the X points but not around the Γ point, indicating areas of strong renormalization located near Γ . The Ce quasiparticle states participate in the formation of hot spots at the Fermi surface, whereas the incoherent f states hybridize and lead to the emergence of dispersive features absent in the non-f counterpart BaB₆. Our results provide an understanding of the electronic structure in rare-earth hexaborides, which will be useful in elucidating the nature of the exotic low-temperature phases in these materials.