  We investigate the electronic structure of a novel Kondo lattice system
CeCuX2 (X = As/Sb) employing high resolution depth-resolved photoemission
spectroscopy of high quality single crystalline materials. CeCuSb2 and CeCuAs2
represent different regimes of the Doniach phase diagram exhibiting Kondo-like
transport properties and CeCuSb2 is antiferromagnetic (TN ~ 6.9 K) while
CeCuAs$_2$ does not show long-range magnetic order down to the lowest
temperature studied. In this study, samples were cleaved in ultrahigh vacuum
before the photoemission measurements and the spectra at different surface
sensitivity establish the pnictogen layer having squarenet structure as the
terminated surface which is weakly bound to the other layers. Cu 2p and As 2p
spectra show spin-orbit split sharp peaks along with features due to plasmon
excitations. Ce 3d spectra exhibit multiple features due to the hybridization
of the Ce 4f/5d states with the valence states. While overall lineshape of the
bulk spectral functions look similar in both the cases, the surface spectra are
very different; the surface-bulk difference is significantly weaker in CeCuAs2
compared to that observed in CeCuSb2. A distinct low binding energy peak is
observed in the Ce 3d spectra akin to the scenario observed in cuprates and
manganites due to the Zhang-Rice singlets and/or high degree of itineracy of
the conduction holes. The valence band spectra of CeCuSb$_2$ manifest highly
metallic phase. In CeCuAs2, intensity at the Fermi level is significantly small
suggesting a pseudogap-type behavior. These results bring out an interesting
scenario emphasizing the importance and subtlety of hybridization physics
underlying the exoticity of this novel Kondo system.
