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Title: Indication of subdominant d-wave interaction in superconducting CaKFe 4 As 4

We report inelastic light scattering results on the stoichiometric and fully ordered superconductor CaKFe 4 As 4 as a function of temperature and light polarization. In the energy range between 10 and 315 cm -1 (1.24 and 39.1 meV) we observe the particle-hole continuum above and below the superconducting transition temperature T c and seven of the eight Raman active phonons. The main focus is placed on the analysis of the electronic excitations. Below T c all three symmetries projected with in-plane polarizations display a redistribution of spectral weight characteristic for superconductivity. The energies of the pair-breaking peaks in A 1g and B 2g symmetry are in approximate agreement with the results from photoemission studies. In B 1g symmetry the difference between the normal and superconducting state is most pronounced, and the feature is shifted downwards with respect to those in A 1g and B 2g symmetry. The maximum peaking at 134 cm -1 (16.6 meV) has a substructure on the high-energy side. We interpret the peak at 134 cm -1 in terms of a collective Bardasis-Schrieffer (BS) mode and the substructure as a remainder of the pair-breaking feature on the electron bands. Finally, there is a very weak peakmore » at 50 cm -1 (6.2 meV) which is tentatively assigned to another BS mode.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Bayerische Akademie der Wissenschaften, Garching (Germany). Walther Meissner Inst.; Technical University of Munich, Garching (Germany). Fakultät für Physik E23
  2. Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  3. Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy; Ames Lab., Ames, IA (United States). Division of Materials Science and Engineering
  4. Ames Lab., Ames, IA (United States). Division of Materials Science and Engineering; Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  5. Univ. of Belgrade, Belgrade (Serbia). Center for Solid State Physics and New Materials, Inst. of Physics Belgrade
  6. Bavarian Academy of Sciences and Humanities, Garching (Germany). Walther Meissner Inst.
Publication Date:
Report Number(s):
IS-J-9711
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:
56267076; 57142964; AC02-07CH11358; GBMF4411
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 98; Journal Issue: 2; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; German Academic Exchange Service (DAAD); Serbian Ministry of Education, Science and Technological Development; Gordon and Betty Moore Foundation (GBMF); USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1464473
Alternate Identifier(s):
OSTI ID: 1460127