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arXiv · 1404.5473

SrPt$_3$P: two-band single-gap superconductor

Abstract

The magnetic penetration depth ($\lambda$) as a function of applied magnetic field and temperature in SrPt$_3$P($T_c\simeq8.4$ K) was studied by means of muon-spin rotation ($\mu$SR). The dependence of $\lambda^{-2}$ on temperature suggests the existence of a single $s-$wave energy gap with the zero-temperature value $\Delta=1.58(2)$ meV. At the same time $\lambda$ was found to be strongly field dependent which is the characteristic feature of the nodal gap and/or multi-gap systems. The multi-gap nature of the superconduicting state is further confirmed by observation of an upward curvature of the upper critical field. This apparent contradiction would be resolved with SrPt$_3$P being a two-band superconductor with equal gaps but different coherence lengths within the two Fermi surface sheets.

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R. Khasanov, A. Amato, P. K. Biswas, H. Luetkens, N. D. Zhigadlo, B. Batlogg. 2014-04-22. SrPt$_3$P: two-band single-gap superconductor. https://doi.org/10.1103/physrevb.90.140507

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