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Title: Universal doping evolution of the superconducting gap anisotropy in single crystals of electron-doped Ba(Fe 1–xRh x) 2As 2 from London penetration depth measurements

Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe 1–xRh x) 2As 2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth Δλ( T). Single crystals with doping levels representative of an underdoped regime x = 0.039 ( T c = 15.5 K), close to optimal doping x = 0.057 ( T c = 24.4 K) and overdoped x = 0.079 ( T c = 21.5 K) and x = 0.131( T c = 4.9 K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n, by fitting the data to the power-law, Δλ = AT n. The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe 2As 2 and 3d-electron-doped Ba(Fe,Co) 2As 2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-dopedmore » sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co) 2As 2 samples. In conclusion, our study supports the universal superconducting gap variation with doping and pairing at least in iron based superconductors of the BaFe 2As 2 family.« less
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [2] ;  [2] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States); Univ. of Maryland, College Park, MD (United States)
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States)
  3. Ames Lab. and Iowa State Univ., Ames, IA (United States); Ramapo College of New Jersey, Mahwah, NJ (United States)
Publication Date:
Report Number(s):
IS-J-9665
Journal ID: ISSN 0953-8984
Grant/Contract Number:
AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 30; Journal Issue: 22; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; superconductivity; London penetration depth; superfluid density; Fe-based superconductivity
OSTI Identifier:
1439427

Kim, Hyunsoo, Tanatar, M. A., Martin, C., Blomberg, E. C., Ni, Ni, Bud'ko, S. L., Canfield, P. C., and Prozorov, R.. Universal doping evolution of the superconducting gap anisotropy in single crystals of electron-doped Ba(Fe1–xRhx)2As2 from London penetration depth measurements. United States: N. p., Web. doi:10.1088/1361-648X/aabef9.
Kim, Hyunsoo, Tanatar, M. A., Martin, C., Blomberg, E. C., Ni, Ni, Bud'ko, S. L., Canfield, P. C., & Prozorov, R.. Universal doping evolution of the superconducting gap anisotropy in single crystals of electron-doped Ba(Fe1–xRhx)2As2 from London penetration depth measurements. United States. doi:10.1088/1361-648X/aabef9.
Kim, Hyunsoo, Tanatar, M. A., Martin, C., Blomberg, E. C., Ni, Ni, Bud'ko, S. L., Canfield, P. C., and Prozorov, R.. 2018. "Universal doping evolution of the superconducting gap anisotropy in single crystals of electron-doped Ba(Fe1–xRhx)2As2 from London penetration depth measurements". United States. doi:10.1088/1361-648X/aabef9.
@article{osti_1439427,
title = {Universal doping evolution of the superconducting gap anisotropy in single crystals of electron-doped Ba(Fe1–xRhx)2As2 from London penetration depth measurements},
author = {Kim, Hyunsoo and Tanatar, M. A. and Martin, C. and Blomberg, E. C. and Ni, Ni and Bud'ko, S. L. and Canfield, P. C. and Prozorov, R.},
abstractNote = {Doping evolution of the superconducting gap anisotropy was studied in single crystals of 4d-electron doped Ba(Fe1–xRhx)2As2 using tunnel diode resonator measurements of the temperature variation of the London penetration depth Δλ(T). Single crystals with doping levels representative of an underdoped regime x = 0.039 (Tc = 15.5 K), close to optimal doping x = 0.057 (Tc = 24.4 K) and overdoped x = 0.079 (Tc = 21.5 K) and x = 0.131(Tc = 4.9 K) were studied. Superconducting energy gap anisotropy was characterized by the exponent, n, by fitting the data to the power-law, Δλ = ATn. The exponent n varies non-monotonically with x, increasing to a maximum n = 2.5 for x = 0.079 and rapidly decreasing towards overdoped compositions to 1.6 for x = 0.131. This behavior is qualitatively similar to the doping evolution of the superconducting gap anisotropy in other iron pnictides, including hole-doped (Ba,K)Fe2As2 and 3d-electron-doped Ba(Fe,Co)2As2 superconductors, finding a full gap near optimal doping and strong anisotropy toward the ends of the superconducting dome in the T-x phase diagram. The normalized superfluid density in an optimally Rh-doped sample is almost identical to the temperature-dependence in the optimally doped Ba(Fe,Co)2As2 samples. In conclusion, our study supports the universal superconducting gap variation with doping and pairing at least in iron based superconductors of the BaFe2As2 family.},
doi = {10.1088/1361-648X/aabef9},
journal = {Journal of Physics. Condensed Matter},
number = 22,
volume = 30,
place = {United States},
year = {2018},
month = {5}
}