Jang Sooyoung, Denlinger J D, Allen J W, Zapf V S, Maple M B, Kim Jae Nyeong, Jang Bo Gyu, Shim Ji Hoon
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
Proc Natl Acad Sci U S A. 2020 Sep 22;117(38):23467-23476. doi: 10.1073/pnas.2001778117. Epub 2020 Sep 4.
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 CeCoIn 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, [Formula: see text] 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 [Formula: see text] is specifically highlighted. A recent ARPES report of low T Luttinger theorem failure for CeCoIn is shown to be unjustified by current ARPES data and is not found in the theory.
近藤晶格随温度的演化是理论和实验研究的一个长期课题，但它缺乏对基本的f - c杂化过程与近藤屏蔽和费米液体晶格相干性的基本温度尺度之间关系的真正微观描述。在此，利用f共振角分辨光电子能谱（ARPES）对近藤晶格系统CeCoIn中f - c杂化能带色散和费米能f谱权重的温度依赖性进行了详细研究，以便能够直接与包含晶体电场态完全真实情况的第一性原理动态平均场理论（DMFT）计算进行比较。对于两个正交的（001）和（100）解理面以及三种不同的f - c杂化构型的ARPES结果，结合DMFT提供的额外微观见解，揭示了在比晶格相干温度[公式：见正文]K高得多的温度下f对费米面的贡献，通常认为该温度是这种行为的起始温度。DMFT结果显示了晶体电场（CEF）分裂在这种行为中的作用，并特别强调了在[公式：见正文]以下的与温度相关的CEF简并度交叉。最近一份关于CeCoIn在低温下卢廷格定理失效的ARPES报告被证明与当前的ARPES数据不符，并且在理论中也未发现。
