Unconventional multiband superconductivity with nodes in single-crystalline SrFe2(As_0.65P_0.35)2 as seen via 31P-NMR and specific heat

Abstract

We report 31P-NMR and specific heat measurements on an iron (Fe)-based superconductor SrFe2(As0.65P0.35)2 with Tc=26 K, which have revealed the development of antiferromagnetic correlations in the normal state and the unconventional superconductivity(SC) with nodal gap dominated by the gapless low-lying quasiparticle excitations. The results are consistently argued with an unconventional multiband SC state with the gap-size ratio of different bands being significantly large; the large full gaps in s\pm-wave state keep Tc high, whereas a small gap with a nodal-structure causes gapless feature under magnetic field. The present results will develop an insight into the strong material dependence of SC-gap structure in Fe-based superconductors.

6 pages, 5 figures, 1 table

References in corpus (8)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Microwave Penetration Depth and Quasiparticle Conductivity in PrFeAsO_1-y Single Crystals : Evidence for a Full-Gap Superconductor
• Strong-coupling Spin-singlet Superconductivity with Multiple Full Gaps in Hole-doped Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Probed by Fe-NMR
• 75As NMR Study of Hole-Doped Superconductor Ba1-xKxFe2As2 (Tc = 38K)
• Nodal gap structure of BaFe_2(As_{1-x}P_x)_2 from angle-resolved thermal conductivity in a magnetic field
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Volovik effect in a highly anisotropic multiband superconductor: experiment and theory

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• Comparative study of the effects of electron irradiation and natural disorder in single crystals of SrFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ ($x=$0.35) superconductor
• Emergent Phases of Nodeless and Nodal Superconductivity Separated by Antiferromagnetic Order in Iron-based Superconductor (Ca4Al2O6)Fe2(As1-xPx)2: 75As- and 31P-NMR Studies
• Nodal superconductivity in isovalently substituted SrFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ pnictide superconductor at the optimal doping, $x=$0.35
• The change of electronic state and crystal structure by post-annealing in superconducting SrFe2(As0.65P0.35)2
• Electronic Phase Diagram of SrFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$: Effect of Structural Dimensionality
• High-Tc Nodeless s_\pm-wave Superconductivity in (Y,La)FeAsO_{1-y} with Tc=50 K: 75As-NMR Study
• Strongly three-dimensional electronic structure and Fermi Surfaces of SrFe${}_2$(As${}_{0.65}$P${}_{0.35}$)${}_2$: Comparison with BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• NMR evidence for an intimate relationship between antiferromagnetic spin fluctuations and extended s-wave superconductivity in mono-crystalline SrFe2(As_{1-x}P_{x})2
• NMR Investigation of the iron-based superconductors Ca4(Mg,Ti)3Fe2As2O8-y and Ca5(Sc,Ti)4Fe2As2O11-y
• Single crystal growth and physical properties of SrFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• High-$T_c$ Iron-phosphide Superconductivity Enhanced by Reemergent Antiferromagnetic Spin Fluctuations in (Sr${}_4$Sc${}_2$O${}_6$)Fe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ probed by NMR
• Unconventional Multi-gap Superconductivity and Antiferromagnetic Spin Fluctuations in New Iron-arsenide LaFe2As2 in Heavily Electron-doped Regime
• Scanning Tunneling Spectroscopy on SrFe${}_2$(As${}_{1-\mathrm{x}}$P${}_{\mathrm{x}}$)${}_2$
• Electronic Structure of ${\mathrm{Sr}}_{1-y}{\mathrm{Ca}}_y\mathrm{F}{\mathrm{e}}_2({\mathrm{As}}_{1-x}{\mathrm{P}}_x{)}_2$ ($x$ = 0.25, $y$ = 0.08) Revealed by Angle-Resolved Photoemission Spectroscopy
• Band-dependent superconducting gap in SrFe${}_2$(As${}_{0.65}$P${}_{0.35}$)${}_2$ studied by angle-resolved photoemission spectroscopy