Weak superconducting pairing and a single isotropic energy gap in stoichiometric LiFeAs

Abstract

We report superconducting (SC) properties of stoichiometric LiFeAs (Tc = 17 K) studied by small-angle neutron scattering (SANS) and angle-resolved photoemission (ARPES). Although the vortex lattice exhibits no long-range order, well-defined SANS rocking curves indicate better ordering than in chemically doped 122-compounds. The London penetration depth of 210 nm, determined from the magnetic field dependence of the form factor, is compared to that calculated from the ARPES band structure with no adjustable parameters. Its temperature dependence is best described by a single isotropic SC gap of 3.0 meV, which agrees with the ARPES value of 3.1 meV and corresponds to the ratio 2Delta/kTc = 4.1, approaching the weak-coupling limit predicted by the BCS theory. This classifies LiFeAs as a weakly coupled single-gap superconductor, similar to conventional metals.

4 pages, 4 figures

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Cited by in corpus (46)

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• Unconventional Anisotropic s-Wave Superconducting Gaps of LiFeAs Iron-Pnictide Superconductor
• One-sign order parameter in iron based superconductor
• Crossover from weak to strong pairing in unconventional superconductors
• Nodeless vs nodal order parameters in LiFeAs and LiFeP superconductors
• Renormalization group flow, competing phases, and the structure of superconducting gap in multi-band models of Iron based superconductors
• Fishtail effect and vortex dynamics in LiFeAs single crystals
• Unconventional superconducting gap in NaFe${}_{0.95}$Co${}_{0.05}$As observed by angle-resolved photoemission spectroscopy
• Phase Diagram and Calorimetric Properties of NaFe${}_{1-x}$Co${}_x$As
• The superconducting gaps in LiFeAs: Joint study of specific heat and ARPES
• Gap Symmetry in KFe_2As_2 and cos 4θgap component in LiFeAs
• Universal Lower Limit on Vortex Creep in Superconductors
• Time of life as it is in LiFeAs
• The pairing state in KFe2As2 studied by measurements of the magnetic vortex lattice
• Strong pairing at iron $3d_{xz,yz}$ orbitals in hole-doped BaFe${}_2$As${}_2$
• 20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
• NMR evidence of strong-correlated superconductivity in LiFeAs: tuning toward an SDW ordering
• An ARPES view on the high-Tc problem: phonons vs spin-fluctuations
• Microwave Surface Impedance Measurements of LiFeAs Single Crystals
• Small anisotropy of the lower critical field and $s_{\pm }$-wave two-gap feature in single crystal LiFeAs
• Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements
• Single crystal growth and superconducting properties of LiFeAs
• 75As NMR-NQR study in superconducting LiFeAs
• Quantitative assessment of pinning forces and the superconducting gap in NbN thin films from complementary magnetic force microscopy and transport measurements
• Competition between superconductivity and magnetic/nematic order as a source of anisotropic superconducting gap in underdoped Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$
• Magnetic-field-induced nonlocal effects on the vortex interactions in twin-free YBa2Cu3O7
• A weak-coupling superconductivity in the electron doped NaFe${}_{0.95}$Co${}_{0.05}$As is revealed by ARPES
• Vector field controlled vortex lattice symmetry in LiFeAs
• Achieving the depairing limit along $c$ axis in Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$ single crystals
• Magnetic field - dependent Labusch parameter in LiFeAs superconductor from Campbell penetration depth
• Raman Scattering Study of the Lattice Dynamics of Superconducting LiFeAs
• Disordered hyperuniformity in superconducting vortex lattices
• Anomalous hysteresis as an evidence for a magnetic field-induced chiral superconducting state in LiFeAs
• Evidence for conventional superconductivity in SrPd2Ge2
• Vortex lattice structure in BaFe2(As0.67P0.33)2 by the small-angle neutron scattering technique
• Investigation of LiFeAs by means of "Break-junction" Technique
• Optical properties of iron-based superconductor LiFeAs single crystal
• Coexistence of Clean- and Dirty-limit Superconductivity in LiFeAs
• Probing the Order Parameter of Superconducting LiFeAs using Pb/LiFeAs and Au/LiFeAs Point-Contact Spectroscopy
• Optical Conductivity Evidence of Clean-Limit Superconductivity in LiFeAs
• Absence of hexagonal to square structural transition in LiFeAs vortex matter
• Reversible ordering and disordering of the vortex lattice in UPt3
• Nodal superconducting gap in LiFeP revealed by NMR: contrast with LiFeAs