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

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 117; no. 38; pp. 23467 - 23476
• Main Authors: Jang, Sooyoung, Denlinger, J. D., Allen, J. W., Zapf, V. S., Maple, M. B., Kim, Jae Nyeong, Jang, Bo Gyu, Shim, Ji Hoon
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 22-09-2020; Proceedings of the National Academy of Sciences
• Subjects: ARPES; CEF; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Coherence; Crossovers; Crystal structure; Crystallinity; DMFT; Electric fields; Electronic structure; Evolution; Fermi surfaces; First principles; High Magnetic Field Science; Hybridization; Kondo lattice; Mean field theory; Photoelectric emission; Physical Sciences; Spectroscopy; Temperature; Temperature dependence; Temperature scales; Kondo lattice; CEF; ARPES; DMFT
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2001778117

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 CeCoIn₅ is 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 CeCoIn₅ is shown to be unjustified by current ARPES data and is not found in the theory.