2017/03/31 by Zhitao Zhang, Z. T. Zhang, D. Dmytriieva +12
Materials Science · Physics and Astronomy · #Anisotropy #Condensed matter physics #Exponent #Iron-based superconductors research #Knight shift #Lattice (music) #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Relaxation (psychology) #Superconductivity #Type (biology) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.97.115110
published as Phys. Rev. B 97, 115110 (2018) · 5 pages, 4 figures
openalex publication_date 2018/03/06 · arxiv created 2018/03/07 · arxiv updated 2018/03/08 · openalex created_date 2018/03/29 · openalex updated_date 2026/08/05
We report 75As nuclear magnetic resonance measurements on single crystals of RbFe2As2 and CsFe2As2. Taking previously reported results for KFe2As2 into account, we find that the anisotropic electronic correlations evolve towards a magnetic instability in the AFe2As2 series (with A=K, Rb, Cs). Upon isovalent substitution with larger alkali-metal ions, a drastic enhancement of the anisotropic nuclear spin-lattice relaxation rate and decreasing Knight shift reveal the formation of pronounced spin fluctuations with stripe-type modulation. Furthermore, a decreasing power-law exponent of the nuclear spin-lattice relaxation rate (1/T1)_H\ensuremath∥ab, probing the in-plane spin fluctuations, evidences an emergent deviation from Fermi-liquid behavior. All these findings clearly indicate that the expansion of the lattice in the AFe2As2 series tunes the electronic correlations towards a quantum critical point at the transition to a yet unobserved ordered phase.