Momentum dependence of the superconducting gap in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$

Abstract

The precise momentum dependence of the superconducting gap in the iron-arsenide superconductor with Tc = 32K (BKFA) was determined from angle-resolved photoemission spectroscopy (ARPES) via fitting the distribution of the quasiparticle density to a model. The model incorporates finite lifetime and experimental resolution effects, as well as accounts for peculiarities of BKFA electronic structure. We have found that the value of the superconducting gap is practically the same for the inner Gamma-barrel, X-pocket, and "blade"-pocket, and equals 9 meV, while the gap on the outer Gamma-barrel is estimated to be less than 4 meV, resulting in 2Delta/kT_c=6.8 for the large gap, and 2Delta/kT_c<3 for the small gap. A large (77 \pm 3%) non-superconducting component in the photoemission signal is observed below T_c. Details of gap extraction from ARPES data are discussed in Appendix.

Images revised; details of gap extraction from ARPES spectra are added as an Appendix

References in corpus (7)

• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• The BCS-like gap in superconductor SmFeAsO_0.85F_0.15
• (pi,pi)-electronic order in iron arsenide superconductors
• Bare electron dispersion from photoemission experiments
• Self-consistent self-energy analysis of photoemission data
• Measuring the gap in ARPES experiments

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• Superconductivity coexisting with phase-separated static magnetic order in (Ba,K)Fe${}_2$As${}_2$, (Sr,Na)Fe${}_2$As${}_2$ and CaFe${}_2$As${}_2$
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• Suppression of the structural phase transition and lattice softening in slightly underdoped Ba(1-x)K(x)Fe2As2 with electronic phase separation
• Fermi surface of Ba{1-x}KxFe2As2 as probed by angle-resolved photoemission
• Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductors