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 Gamma point are strongly renormalized. Our first-principles calculations agree with our experimental results around the X points but not around the Gamma point, indicating areas of strong renormalization located near Gamma. 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.