Title: Evolution of the Kondo lattice electronic structure above the transport coherence temperature,
Abstract: The temperature-dependent evolution of the Kondo lattice is a long-standing
topic of theoretical and experimental investigation and yet it lacks a truly
microscopic description of the relation of the basic $f$-$d$ hybridization
processes to the fundamental temperature scales of Kondo screening and
Fermi-liquid lattice coherence. Here, the temperature-dependence of $f$-$d$
hybridized band dispersions and Fermi-energy $f$ spectral weight in the Kondo
lattice system CeCoIn$_5$ is investigated using $f$-resonant angle-resolved
photoemission (ARPES) with sufficient detail to allow direct comparison to
first principles dynamical mean field theory (DMFT) calculations containing
full realism of crystalline electric field states. The ARPES results, for two
orthogonal (001) and (100) cleaved surfaces and three different $f$-$d$
hybridization scenarios, with additional microscopic insight provided by DMFT,
reveal $f$ participation in the Fermi surface at temperatures much higher than
the lattice coherence temperature, $T^*\approx$ 45 K, commonly believed to be
the onset for such behavior. The identification of a $T$-dependent crystalline
electric field degeneracy crossover in the DMFT theory $below$ $T^*$ is
specifically highlighted.