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TT: Fachverband Tiefe Temperaturen
TT 86: Correlated Electrons: Method Development
TT 86.1: Talk
Friday, March 22, 2024, 09:30–09:45, H 3007
RKKY-induced Kondo suppression in heavy-fermion materials — •Ulli Pohl1 and Johann Kroha1,2 — 1University of Bonn, DE — 2University of St. Andrews, UK
In heavy-fermion (HF) systems, the interplay of the local Kondo exchange interaction and the long-range RKKY interaction, remains a difficult problem. It can control magnetic quantum phase transitions in these materials. Recently, a perturbative, selfconsistent renormalization group technique was developed to include the local Kondo exchange and the RKKY interaction on the same footing [1]. In particular, the RKKY interaction is generated from the local Kondo exchange in second order of perturbation theory, as in realistic systems. In the present work, we extend this theory from weak RKKY interaction, i.e., from the HF-liquid side of a magnetic quantum phase transition (QPT), to strong RKKY interaction, i.e. to the realm where the system orders magnetically at sufficiently low temperatures. While on the HF side of the QPT the Kondo spectral weight develops logarithmically with decreasing temperature T, we find that on the magnetic side of the QPT the Kondo spectral weight is suppressed already at T orders of magnitude higher than the ordering Néel temperature TN. This indicates that the Kondo weight may be destructed not by critical magnetic order-parameter fluctuations, but by frustrating RKKY coupling active at all temperatures. The behavior may be observable in a certain class of HF materials [2].
[1] A. Nejati, K. Ballmann, J. Kroha, PRL 118, 117204 (2017).
[2] C. Wetli. et al., Nature Physics 14, 1103 (2018).
Keywords: Heavy fermions; Quantum phase transitions; RKKY interaction; Renormalization group