학술논문
Mass Enhancements and Band Shifts in Strongly Hole-Overdoped Fe-Based Pnictide Superconductors: KFe2 As2 and CsFe2 As2
Document Type
Academic Journal
Author
Source
Journal of Superconductivity and Novel Magnetism: Incorporating Novel Magnetism. 31(3):777-783
Subject
Language
English
ISSN
1557-1939
1557-1947
1557-1947
Abstract
The interplay of high- and low-energy mass renormalizations with band shifts reflected by the positions of van Hove singularities (VHS) in the normal-state spectrum of the most strongly hole-overdoped correlated AFe2 As2 (A122) with A=K, Cs is discussed phenomenologically from ARPES data and band-structure (GGA) calculations with full spin-orbit coupling. The big increase of the Sommerfeld coefficient γ from K122 to Cs122 is ascribed to an enhanced coupling to low-energy bosons in the vicinity of a quantum critical point to an unknown, yet incommensurate phase different from the commensurate Mott one. We find no sizeable increase in correlations for Cs122 in contrast to Eilers et al. (Phys. Rev. Lett. 116, 237003 2016). The empirical (ARPES) VHS positions as compared with GGA predictions point even to slightly weaker correlations in Cs122 in accord with low-T magnetic susceptibility χ(T) data and a decreasing Wilson ratio ∝ χ(0)/γ.