Multi-gap nodeless superconductivity in iron selenide FeSe${}_x$: evident from quasiparticle heat transport

J. K. Dong, T. Y. Guan, S. Y. Zhou +6

The in-plane thermal conductivity $\kappa$ of the iron selenide superconductor FeSe${}_x$ ($T_c$ = 8.8 K) were measured down to 120 mK and up to 14.5 T ($\simeq 3/4H_{c2}$). In zero fiel…