RKKY coupled local-moment magnetism in NaFe1-xCuxAs

Yizhou Xin*, Ingrid Stolt, Yu Song, Pengcheng Dai, W. P. Halperin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


A central question in a large class of strongly correlated electron systems, including heavy fermion compounds and iron pnictides, is the identification of different phases and their origins. It has been shown that the antiferromagnetic (AFM) phase in some heavy fermion compounds is induced by Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between localized moments, and that the competition between this interaction and Kondo effect is responsible for quantum criticality. However, conclusive experimental evidence of the RKKY interaction in pnictides is lacking. Here, using high resolution Na23 NMR measurements on lightly Cu-doped metallic single crystals of NaFe1-xCuxAs (x≈0.01) and numerical simulation, we show direct evidence of the RKKY interaction in this pnictide system. Aided by computer simulation, we identify the Na23 NMR satellite resonances with the RKKY oscillations of spin polarization at Fe sites. Our Na23 spin-lattice and spin-spin relaxation data exhibit a signature of an itinerant and inhomogeneous AFM phase in this system, accompanied by a simulation of Cu-induced perturbation to the ordered moments on the Fe sites. Our NMR results indicate coexistence of local and itinerant magnetism in lightly Cu-doped NaFe1-xCuxAs.

Original languageEnglish (US)
Article numberA30
JournalPhysical Review B
Issue number14
StatePublished - Oct 1 2021

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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