Distinctive Doping Dependence of Upper Critical Field in Iron-Based Superconductor LaFeAsO_1-xH_x

2023/08/24 by Kawachi, Shiro, Yamaura, Jun-ichi, Kuramoto, Yoshio +7
#FOS: Physical sciences #Superconductivity (cond-mat.supr-con)

paper · doi:10.48550/arxiv.2308.12631

Abstract

High magnetic fields up to 105 T have been utilized in deriving the upper critical field B_{\rm c2} of LaFeAsO_1-xH_x throughout whole temperatures below T_{\rm c}. Resistivity measurements demonstrate that B_{\rm c2} behaves differently in samples with x = 0.12 (SC1) from those with 0.32 (SC2). In SC1, the two-band model assuming the s-wave pairing gives a good fitting with repulsive intraband interaction and dominant interband coupling. In SC2, we have to assume attractive intraband interaction with weak interband coupling, which in fact suggests a non-s-wave pairing in view of the strong Coulomb repulsion. These results support the possibility that SC1 and SC2 have different pairing symmetries.

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