Superconducting Order Parameters in overdoped BaFe${}_{1.86}$Ni${}_{0.14}$As${}_2$ Revealed by Multiple Andreev Reflection Spectroscopy of Planar Break-Junctions

Abstract

Using multiple Andreev reflection (MAR) spectroscopy, we studied superconductor - normal metal - superconductor (SnS) semiballistic contacts with incoherent transport in overdoped pnictide superconductors BaFe${}_{1.86}$Ni${}_{0.14}$As${}_2$ with critical temperature $T_c\approx 12$ K. We directly determined an anisotropic large gap with the characteristic ratios $2{\Delta }_L^{\mathrm{out}}(0)/k_B{T}_c\approx 6$ and $2{\Delta }_L^{\mathrm{in}}(0)/k_B{T}_c\approx 4$, almost isotropic small gap with $2{\Delta }_S(0)/k_B{T}_c\approx 2$, and the temperature dependence of the resolved superconducting order parameters. Above the large gap position $2{\Delta }_L$, a fine dI(V)/dV structure fully vanishing at $T_c$ and possibly caused by a resonant coupling with a bosonic mode was observed.

arXiv comment27 pages, 10 figures

References in corpus (48)

• The pseudogap in high-temperature superconductors: an experimental survey
• High Temperature Superconductivity in Iron Pnictides and Chalcogenides
• AC JOSEPHSON EFFECT IN A SINGLE QUANTUM CHANNEL
• Recent advances in iron-based superconductors toward applications
• Iron based superconductors: magnetism, superconductivity and electronic structure
• Temperature-doping phase diagrams for Ba(Fe1-xTMx)2As2(TM=Ni, Cu, Cu / Co) single crystals
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Orbital selective pairing and gap structures of iron-based superconductors
• Importance of Fermi surface topology for high temperature superconductivity in electron-doped iron arsenic superconductors
• Quantum Materials: Shape Resonances in Superstripes
• Pseudogap formation above the superconducting dome in iron-pnictides
• Spin fluctuations in iron pnictides and chalcogenides: From antiferromagnetism to superconductivity
• Experimental evidence of two-band behavior of MgB2
• Anisotropic Neutron Spin Resonance in Superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Three-dimensional nodal superconducting gap in single crystals Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$
• Intrinsic Josephson junctions in the iron-based multi-band superconductor (V2Sr4O6)Fe2As2
• Break-junction technique in application to layered superconductors (Review article)
• First-Principles Study for the Anisotropy of Iron-based Superconductors toward Power and Device Applications
• Electron doping evolution of the magnetic excitations in BaFe2-xNixAs2
• Nematic Quantum Critical Fluctuations in BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Bulk magnetization and strong intrinsic pinning in Ni-doped BaFe2As2 single crystals
• Possible Sign-Reversing s-Wave Superconductivity in Co-Doped BaFe2As2 Proved by Thermal Transport Measurements
• Origin of diverse nematic orders in Fe-based superconductors: 45${}^{\circ }$ rotated nematicity in AFe${}_2$As${}_2$ (A=Cs, Rb)
• Nodeless superconductivity in the presence of spin-density wave in pnictide superconductors: The case of BaFe${}_{2-x}$Ni${}_x$As${}_2$
• Experimental study of intrinsic multiple Andreev reflections effect in GdO(F)FeAs superconductor array junctions
• Leggett mode in a strong-coupling model of iron arsenide superconductors
• Evidence of hot and cold spots on the Fermi surface of LiFeAs
• Evolution of Superconducting Gaps in Th-Substituted Sm${}_{1-x}$Th${}_x$OFeAs Studied by Multiple Andreev Reflection Spectroscopy
• Amplitudes of minima in dynamic conductance spectra of the SNS Andreev contact
• On the Structure of Superconducting Order Parameter in High-Temperature Fe-Based Superconductors
• Spin resonance peak in Fe-based superconductors with unequal gaps
• Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials
• Hidden antiferro-nematic order in Fe-based superconductor BaFe${}_2$As${}_2$ and NaFeAs above $T_S$
• Energy scale of nematic ordering in the parent iron-based superconductor:BaFe2As2
• Linkage between scattering rates and superconductivity in doped ferropnictides
• Experimental elucidation of the origin of the `double spin resonances' in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• In-plane anisotropy of transport coefficients in the electronic nematic states: Universal origin of the nematicity in Fe-based superconductors
• Exploring of point-contact spectra of Ba1-xNaxFe2As2 in the normal and superconducting state
• Structure of the pairing gap from orbital nematic fluctuations
• Optical and Hidden Transport Properties of BaFe${}_{1.91}$Ni${}_{0.09}$As${}_2$ Film
• Superconducting Order Parameter and Bosonic Mode in Hydrogen-Substituted NdFeAsO${}_{0.6}$H${}_{0.36}$ Revealed by Multiple Andreev Reflection Spectroscopy
• Gap Anisotropy in Iron-Based Superconductors: A Point-Contact Andreev Reflection Study of BaFe${}_{2-x}$Ni${}_x$As${}_2$ Single Crystals
• THz phonon spectroscopy of doped superconducting cuprates
• Superconducting gap symmetry in BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$ superconductor
• Pairing mechanism for nodal $s$-wave superconductivity in BaFe${}_2$(As,P)${}_2$: Analysis beyond Migdal-Eliashberg formalism
• Variety of c-axis collective excitations in layered multigap superconductors
• Evidence of a multiple boson emission in Sm${}_{1-x}$Th${}_x$OFeAs
• Doping evolution of the gap structure and spin-fluctuation pairing in $Ba(F{e}_{1-x}C{o}_x{)}_{2}A{s}_2$ superconductors