Angle-resolved photoemission spectroscopy view on the nature of Ce 4f electrons in the antiferromagnetic Kondo lattice CePd5Al2

Abstract

We report an angle-resolved photoemission spectroscopy study of the antiferromagnetic Kondo lattice $\mathrm{Ce}{\mathrm{Pd}}_{5}{\mathrm{Al}}_{2}$, focusing on the quasi-two-dimensional $k$-space nature of its Fermi surface and, tuning photon energy to the Ce $4d--4f$ on-resonance transition, the hybridization of the Ce $4f$ state. A strong shoulder feature on the ${f}^{0}$ peak was detected, suggesting hybridization between conduction and $f$ bands. On-resonance spectra revealed narrow, yet hybridized quasiparticle bands with sharp peaks and $\ensuremath{\sim}$ 9 meV energy dispersion near the Fermi energy ${E}_{F}$. The observed dispersive hybridized $f$ band can be well described by a hybridization-band picture based on the periodic Anderson model (PAM). Hence, the $4f$ electrons in $\mathrm{Ce}{\mathrm{Pd}}_{5}{\mathrm{Al}}_{2}$ display a dual nature, with both localized and itinerant features, but with dominantly localized character.