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Title: Unified description of superconducting pairing symmetry in electron-doped Fe-based-122 compounds

Here, the pairing symmetry is examined in highly electron-doped Ba (Fe 1-x Co x As) 2 and A y Fe 2 Se 2 (with A = K, Cs) compounds, with similar crystallographic and electronic band structures. Starting from a phenomenological two-orbital model, we consider nearest-neighbor and next-nearest-neighbor intraorbital pairing interactions on the Fe square lattice. In this model, we find a unified description of the evolution from s ±-wave pairing (2.0 < n ≲ 2.4) to d-wave pairing (2.4 ≲ n ≲ 2.5) as a function of electron filling. In the crossover region, a time-reversal symmetry breaking s ± + id pairing state emerges. This minimal model offers an overall picture of the evolution of superconductivity with electron doping for both s ±-wave and d-wave pairings, as long as the dopants only play the role of a charge reservoir. However, the situation is more complicated for Ba (Fe 1-x Co x As) 2. A real-space study further shows that when the impurity scattering effects of Co dopants are taken into account, the superconductivity is completely suppressed for n > 2.4. This preempts any observation of d-wave pairing in this compound, in contrast to A y Fe 2 Se 2 withmore » 0.8 < y < 1.0.« less
Authors:
 [1] ;  [2] ;  [3] ; ORCiD logo [3] ; ORCiD logo [3] ;  [1] ;  [1]
  1. Univ. of Houston, TX (United States). Dept. of Physics and Texas Center for Superconductivity
  2. Univ. of Houston, TX (United States). Dept. of Physics and Texas Center for Superconductivity; Yangzhou Univ. (China). School of Physics Science and Technology
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-15-22100
Journal ID: ISSN 1098-0121; PRBMDO
Grant/Contract Number:
AC52-06NA25396; DMR-1206839; E-1146
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 91; Journal Issue: 22; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF); Robert A. Welch Foundation
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1457233
Alternate Identifier(s):
OSTI ID: 1198527