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arXiv · 1611.04726

Superconducting gap structure in ambient-pressure-grown $\mathrm{LaO_{0.5}F_{0.5}BiS_{2}}$

Jian Zhang·K. Huang·Z. F. Ding·D. E. MacLaughlin·O. O. Bernal·P. -C. Ho·C. Tan·X. Liu·D. Yazici·M. B. Maple·Lei Shu
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Abstract

We have performed transverse-field muon spin relaxation (TF-$μ$SR) measurements on ambient-pressure-grown polycrystalline $\mathrm{LaO_{0.5}F_{0.5}BiS_{2}}$. From these measurements, no signature of magnetic order is found down to 25 mK. The value of the magnetic penetration depth extrapolated to 0 K is 0.89 (5) $μ$m. The temperature dependence of superconducting penetration depth is best described by either a multigap s + s-wave model with $Δ_{1}$ = 0.947 (7) meV and $Δ_{2}$ = 0.22 (4) meV or the ansiotropic s-wave model with $Δ(0)$ = 0.776 meV and anisotropic gap amplitude ratio $Δ_{min}/Δ_{max}$ = 0.34. Comparisons with other potentially multigap $\mathrm{BiS_{2}}$-based superconductors are discussed. We find that these $\mathrm{BiS_{2}}$-based superconductors, including $\mathrm{Bi_{4}O_{4}S_3}$ and the high-pressure synthesized $\mathrm{LaO_{0.5}F_{0.5}BiS_{2}}$, generally conform to the Uemura relation.

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Jian Zhang, K. Huang, Z. F. Ding, D. E. MacLaughlin, O. O. Bernal, P. -C. Ho, C. Tan, X. Liu, D. Yazici, M. B. Maple, Lei Shu. 2016-11-15. Superconducting gap structure in ambient-pressure-grown $\mathrm{LaO_{0.5}F_{0.5}BiS_{2}}$. https://doi.org/10.1103/physrevb.94.224502

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