Fig. 1: Emergence of a coherent Kondo lattice state as a function of temperature in CePd₃.

a–c Real-space impressions of the increasingly coherent screening of Ce moments (black arrows) across the temperature scales T_K and T_coh. Spins of itinerant electrons are represented by red arrows (see text for details). d–f Electronic spectral function A(k, ω) of CePd₃ obtained from the combination of density functional and dynamical mean field theory (DFT+DMFT) at 1000 K, 400 K, and 116 K. The fourteen 4f orbitals of cerium form seven Kramers doublets, separated into a J = 5/2 sextuplet and a J = 7/2 octuplet by E_SO ≈ 280 meV. A cubic crystal field (CF) further induces a E_SO ≈ 10 meV splitting between a J = 5/2Γ₇ doublet (blue) and the Γ₈ quartet (red). The J = 7/2 states are split into two doublets (purple and orange) and one quartet (green). a, d Above the Kondo temperature, T_K ≈ 600 K, local f-electron moments are uncorrelated. The corresponding electronic structure only shows weak hybridization with the incoherent f-states. b, e For T < T_K, local f-electron magnetic moments effectively couple to the surrounding conduction electrons, forming virtual-bound states in the vicinity of the Fermi energy E_F (suggested as ripples in b). The f spectral weight close to the Fermi surface remains predominantly incoherent. c, f Below the coherence temperature T_coh ≈ 130 K, the f-states are coherently incorporated (suggested by the lattice-coherent modulation in Panel c) into the underlying band structure as dispersive, albeit heavy, electronic quasiparticles. The right panel shows the density of states (DOS) summed over the displayed high-symmetry directions, projected onto the different CF characters.