Multigap superconductivity in sesquicarbides La2C3 and Y2C3
Abstract
A complex structure of the superconducting order parameter in Ln2C3 (Ln = La, Y) is demonstrated by muon spin relaxation (μSR) measurements in their mixed state. The muon depolarization rate [σ v(T)] exhibits a characteristic temperature dependence that can be perfectly described by a phenomenological double-gap model for nodeless superconductivity. While the magnitude of two gaps is similar between La2C3 and Y2C3, a significant difference in the interband coupling between those two cases is clearly observed in the behavior of σ v(T).
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