Nodal superconductivity in Ba(Fe${}_{1-x}$Ru${}_x$)${}_2$As${}_2$ induced by isovalent Ru substitution

Abstract

We present the ultra-low-temperature heat transport study of an iron-based superconductor Ba(Fe${}_{0.64}$Ru${}_{0.36}$)${}_2$As${}_2$ ($T_c$ = 20.2 K), in which the superconductivity is induced by isovalent Ru substitution. In zero field we find a large residual linear term ${\kappa }_0/T$, more than 40% of the normal-state value. At low field, the ${\kappa }_0/T$ shows an $H^{1/2}$ dependence. These provide strong evidences for nodes in the superconducting gap of Ba(Fe${}_{0.64}$Ru${}_{0.36}$)${}_2$As${}_2$, which mimics that in another isovalently substituted superconductor BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$. Our results show that the isovalent Ru substitution can also induce nodal superconductivity in BaFe${}_2$As${}_2$, as P does, and they may have the same origin. We further compare them with other two nodal superconductors LaFePO and LiFeP.

4 pages, 4 figures

Cited by in corpus (2)

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