Nodal multigap superconductivity in the anisotropic iron-based compound RbCa2Fe4As4F2

Abstract

The 12442 compounds are a recently discovered family of iron-based superconductors, that share several features with the cuprates due to their strongly anisotropic structure, but are so far poorly understood. Here, we report on the gap structure and anisotropy of RbCa2(Fe1-xNix)4As4F2 single crystals, investigated by a combination of directional point-contact Andreev-reflection spectroscopy and coplanar waveguide resonator measurements. Two gaps were identified, with clear signatures of d-wave-like nodal structures which persist upon Ni doping, well described by a two-band d-d state with symmetry-imposed nodes. A large London penetration depth anisotropy was revealed, weakly dependent on temperature and fully compatible with the d-d model.

arXiv comment9 pages, 4 figures

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Cited by in corpus (9)

• Spectroscopic studies of the superconducting gap in the 12442 family of iron-based compounds
• Evidence of electron interaction with an unidentified bosonic mode in superconductor CsCa${}_2$Fe${}_4$As${}_4$F${}_2$
• Unusually weak irradiation effects in anisotropic iron-based superconductor RbCa2Fe4As4F2
• Superconductivity of Co-Doped CaKFe4As4 Investigated via Point-Contact Spectroscopy and London Penetration Depth Measurements
• Multiband superconductivity and a deep gap minimum from the specific heat in KCa${}_2$(Fe${}_{1-x}$Ni${}_x$)${}_4$As${}_4$F${}_2$ ($x$ = 0, 0.05, 0.13)
• Vortex matter and strong pinning in underdoped PrFeAs(O,F) with atomic-sized defects
• Intrinsic coherence length anisotropy in nickelate, and some pnictide, and chalcogenide superconductors
• Decoupled interband pairing in a bilayer iron-based superconductor evidenced by ultrahigh-resolution ARPES
• Direct evidence for two-gap superconductivity in hydrogen-intercalated titanium diselenide