Evolution of the Kondo lattice electronic structure above the transport coherence temperature

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-c hybridization processes to the fundamental temperature scales of Kondo screening and Fermi-liquid lattice coherence. Here, the temperature dependence of f-c hybridized band dispersions and Fermi-energy f spectral weight in the Kondo lattice system CeCoIn5is investigated using f-resonant angle-resolved photoemission spectroscopy (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-c hybridization configurations, with additional microscopic insight provided by DMFT, reveal f participation in the Fermi surface at temperatures much higher than the lattice coherence temperature,$T*≈45$K, commonly believed to be the onset for such behavior. The DMFT results show the role of crystalline electric-field (CEF) splittings in this behavior and a T-dependent CEF degeneracy crossover below$T*$is specifically highlighted. A recent ARPES report of low T Luttinger theorem failure for CeCoIn5is shown to be unjustified by current ARPES data and is not found in the theory.

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Award ID(s):
Publication Date:
NSF-PAR ID:
10190686
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
117
Issue:
38
Page Range or eLocation-ID:
p. 23467-23476
ISSN:
0027-8424
Publisher:
Proceedings of the National Academy of Sciences
National Science Foundation
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