ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$

N. Xu; P. Richard; X. -P. Wang; X. Shi; A. van Roekeghem; T. Qian; E. Ieki; K. Nakayama; T. Sato; E. Rienks; S. Thirupathaiah; J. Xing; H. -H. Wen; M. Shi; T. Takahashi; H. Ding

doi:10.1103/physrevb.87.094513

arXiv · 1211.2080

ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$

N. Xu·P. Richard·X. -P. Wang·X. Shi·A. van Roekeghem·T. Qian·E. Ieki·K. Nakayama·T. Sato·E. Rienks·S. Thirupathaiah·J. Xing·H. -H. Wen·M. Shi·T. Takahashi·H. Ding

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Abstract

We used high-energy resolution angle-resolved photoemission spectroscopy to extract the momentum dependence of the superconducting gap of Ru-substituted Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$ ($T_c = 15$ K). Despite a strong out-of-plane warping of the Fermi surface, the magnitude of the superconducting gap observed experimentally is nearly isotropic and independent of the out-of-plane momentum. More precisely, we respectively observed 5.7 meV and 4.5 meV superconducting gaps on the inner and outer $Γ$-centered hole Fermi surface pockets, whereas a 4.8 meV gap is recorded on the M-centered electron Fermi surface pockets. Our results are consistent with the $J_1-J_2$ model with a dominant antiferromagnetic exchange interaction between the next-nearest Fe neighbors.

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N. Xu, P. Richard, X. -P. Wang, X. Shi, A. van Roekeghem, T. Qian, E. Ieki, K. Nakayama, T. Sato, E. Rienks, S. Thirupathaiah, J. Xing, H. -H. Wen, M. Shi, T. Takahashi, H. Ding. 2012-11-09. ARPES observation of isotropic superconducting gaps in isovalent Ru-substituted Ba(Fe$_{0.75}$Ru$_{0.25}$)$_2$As$_2$. https://doi.org/10.1103/physrevb.87.094513

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