THz optical response of Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ films analyzed within the three-band Eliashberg s${}_{\pm }$-wave model

Abstract

The uncertainty of the nature of the normal state and superconducting condensate of unconventional superconductors continues to stimulate considerable speculation about the mechanism of superconductivity in these materials. Of particular interest are the type of symmetry of the order parameter and the basic electronic characteristics of the superconducting and normal states. We report the derivation of temperature dependences of the superconducting condensate plasma frequency, superfluid density, and London penetration depth by measuring terahertz spectra of conductivity and dielectric permittivity of the Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ thin films with different Ni concentrations. A comprehensive analysis of the experimental data was performed in the framework of the simple three-band Eliashberg model under the assumption that the superconducting coupling mechanism is mediated by antiferromagnetic spin fluctuations. The results of independent experiments support the choice of model parameters. Based on calculations of the temperature dependences of superconducting gaps, we may conclude that the obtained results are compatible with the scenario, in which Ba(Fe${}_{1-x}$Ni${}_x$)${}_2$As${}_2$ is a multiband superconductor with s${}_{\pm }$-wave pairing symmetry.

arXiv comment26 pages, 9 figures, 2 tables. arXiv admin note: text overlap with arXiv:2006.00522

References in corpus (28)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity in Iron Compounds
• High-temperature superconductivity in iron-based materials
• Gap symmetry and structure of Fe-based superconductors
• Superconductivity at 22 K in Co-doped BaFe2As2 Crystals
• Pairing Symmetry and Pairing State in Ferropnictides: Theoretical Overview
• Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor
• Effect of magnetic and non-magnetic impurities on highly anisotropic superconductivity
• Three-dimensional Resonance in superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Momentum dependence and nodes of the superconducting gap in iron-pnictides
• Effects of magnetism and doping on the electron-phonon coupling in BaFe${}_2$As${}_2$
• Superfluid density and penetration depth in Fe-pnictides
• Crossover from weak to strong pairing in unconventional superconductors
• Band and momentum dependent electron dynamics in superconducting $\mathrm{Ba}(\mathrm{F}{\mathrm{e}}_{1-\mathrm{x}}\mathrm{C}{\mathrm{o}}_{\mathrm{x}}{)}_2\mathrm{A}{\mathrm{s}}_2$ as seen via electronic Raman scattering
• Interband superconductivity: contrasts between BCS and Eliashberg theory
• Eliashberg approach to superconductivity-induced infrared anomalies in Ba0.68K0.32Fe2As2
• Electrodynamics of the Superconducting State in Ultra-Thin Films at THz Frequencies
• Three-band s+- Eliashberg theory and the superconducting gaps of iron pnictides
• Pressure dependence of the upper critical field of MgB2 and of YNi2B2C
• Breakdown of Migdal's theorem and intensity of electron-phonon coupling in high-Tc superconductors
• Optical signature of sub-gap absorption in the superconducting state of Ba(Fe,Co)2As2
• Superconducting properties of Ba(Fe1-xNix)2As2 thin films in high magnetic fields
• Ginzburg-Landau analysis of the critical temperature and the upper critical field for three-band superconductors
• Vortex Structure and Anisotropic Superconducting Gaps in Ba[Fe(Ni)]${}_2$As${}_2$
• Looking at the superconducting gap of iron pnictides
• Superconducting gap symmetry in BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$ superconductor
• THz electrodynamics of BaFe${}_{1.91}$Ni${}_{0.09}$As${}_2$ film analyzed in the framework of multiband Eliashberg theory