2017/07/01 by S. A. Kuzmichev, T. E. Kuzmicheva, N. D. Zhigadlo
Materials Science · Physics and Astronomy · #Boson #Energy (signal processing) #High-temperature superconductivity #Iron-based superconductors research #Measure (data warehouse) #Range (aeronautics) #Rare-earth and actinide compounds #Spectral line #Superconductivity #Topological Materials and Phenomena #cond-mat.supr-con
paper · pdf · doi:10.1209/0295-5075/119/17007
published as EPL, 119 17007 (2017) · 10 pages, 4 figures
openalex publication_date 2017/07/01 · openalex created_date 2017/12/04 · arxiv created 2018/02/02 · arxiv updated 2018/02/05 · openalex updated_date 2026/08/06
We studied a reproducible fine structure observed in dynamic conductance spectra of Andreev arrays in Sm 1− x Th x OFeAs superconductors with various thorium concentrations ( x = 0.08 -- 0.3 ) and critical temperatures T c = 26 -- 50 K . This structure is unambiguously caused by a multiple boson emission (of the same energy) during the process of multiple Andreev reflections. The directly determined energy of the bosonic mode reaches ε 0 = 14.8 ± 2.2 meV for optimal compounds. Within the studied range of T c , this energy as well as the large Δ L and the small Δ S superconducting gaps, nearly scale with critical temperature with the characteristic ratio ε 0 / k B T c ≈ 3.2 (and 2 Δ L / k B T c ≈ 5.3 , respectively) resembling the expected energy Δ L + Δ S of spin resonance and spectral density enhancement in s ± and s + + states, respectively.