Unusual nodal behaviors of the superconducting gap in the iron-based superconductor Ba(Fe${}_{0.65}$Ru${}_{0.35}$)${}_2$As${}_2$: Effects of spin-orbit coupling

Abstract

We have investigated the superconducting gap of optimally doped Ba(Fe${}_{0.65}$Ru${}_{0.35}$)${}_2$As${}_2$ by angle-resolved photoemission spectroscopy (APRES) using bulk-sensitive 7 eV laser and synchrotron radiation. It was found that the gap is isotropic in the $k_x$-$k_y$ plane both on the electron and hole Fermi surfaces (FSs). The gap magnitudes of two resolved hole FSs show similar $k_z$ dependences and decrease as $k_z$ approaches $\sim$ 2$\pi$/$c$ (i.e., around the Z point) unlike the other Fe-based superconductors reported so far, where the superconducting gap of only one hole FS shows a strong $k_z$ dependence. This unique gap structure can be understood in the scenario that the $d_{z^2}$ orbital character is mixed into both hole FSs due to the finite spin-orbit coupling between almost degenerate FSs and is reproduced by calculations within the random phase approximation including the spin-orbit coupling.

References in corpus (19)

• Gap symmetry and structure of Fe-based superconductors
• Line nodes in the energy gap of high-temperature superconducting BaFe_2(As_{1-x}P_x)_2 from penetration depth and thermal conductivity measurements
• Unprecedented anisotropic metallic state in BaFe2As2 revealed by optical spectroscopy
• Nodal superconducting gap structure in ferropnictide superconductor BaFe2(As0.7P0.3)2
• Hole and Electron Contributions to the Transport Properties of Ba(Fe_(1-x)Ru_x)_2As_2 Single Crystals
• Physical and magnetic properties of Ba(Fe${}_{1-x}$Ru${}_x$)${}_2$As${}_2$ single crystals
• Possible three dimensional nodes in the $s\pm$ superconducting gap of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Manifestations of multiple-carrier charge transport in the magnetostructurally ordered phase of undoped BaFe${}_2$As${}_2$
• Significant reduction of electronic correlations upon isovalent Ru substitution of BaFe2As2
• What controls the phase diagram and superconductivity in Ru substituted BaFe${}_2$As${}_2$?
• Two- and Three-Dimensional Fermi Surfaces and their Nesting Properties in Superconducting BaFe2(As1-xPx)2
• Low-Temperature and High-Energy-Resolution Laser Photoemission Spectroscopy
• Nodal gap structure in Fe-based superconductors due to the competition between orbital and spin fluctuations
• Evidence for exclusion of the possibility of $d$-wave superconducting-gap symmetry in Ba-doped KFe${}_2$As${}_2$
• Evolution of transport properties of BaFe2-xRuxAs2 in a wide range of isovalent Ru substitution
• Effects of Ru Substitution on Dimensionality and Electron Correlations in Ba(Fe_{1-x}Ru_x)_2As_2
• Revisit of the Orbital-Fluctuation-Mediated Superconductivity in LiFeAs: Nontrivial Spin-Orbit Interaction Effects on the Bandstructure and Superconducting Gap Function
• Effects of disordered Ru substitution in BaFe${}_2$As${}_2$: Realization of superdiffusion mechanism in real materials
• ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(Fe${}_{0.75}$Ru${}_{0.25}$)${}_2$As${}_2$

Cited by in corpus (1)

• Influence of Spin Orbit Coupling in the Iron-Based Superconductors