2012/06/30 by Youichi Yamakawa, Seiichiro Onari, Hiroshi Kontani · 4 citations
Materials Science · Physics and Astronomy · #Coherence (philosophical gambling strategy) #Condensed matter physics #Inelastic neutron scattering #Inelastic scattering #Iron-based superconductors research #Pairing #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Rare-earth and actinide compounds #Relaxation (psychology) #Scattering #Scattering rate #Superconductivity #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1088/0953-2048/25/8/084006
published in Superconductor Science and Technology 25(8), 084006 (IOP Publishing) · 9 pages, 6 figures, invited submission to Superconductor Science and Technology focus issue on iron-based superconductors
openalex publication_date 2012/07/17 · arxiv created 2012/07/18 · arxiv updated 2012/07/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present a microscopic study of the nuclear magnetic relaxation rate 1/ T 1 based on the five-orbital model for iron-based superconductors. We mainly discuss the effect of the ‘inelastic’ quasi-particle damping rate γ due to many-body interaction on the size of the coherence peak, for both s ++ and s ± -wave superconducting states. We focus on Ba(Fe 1− x Co x ) 2 As 2 , and systematically evaluate γ in the normal state from the experimental resistivity, from optimally to overdoped compounds. Next, γ in the superconducting state is calculated microscopically based on second-order perturbation theory. In optimally doped compounds ( T c ∼ 30 K), it is revealed that the coherence peak on 1/ T 1 T is completely suppressed due to large γ for both s ++ and s ± -wave states. On the other hand, in heavily overdoped compounds with T c < 10 K, the coherence peak could appear for both pairing states, since γ at T c is quickly suppressed in proportion to . By making careful comparison between theoretical and experimental results, we conclude that it is difficult to discriminate between s ++ and s ± -wave states from the present experimental results.