Multigap Superconductivity in Y${}_2$C${}_3$: A ${}^{13}$C-NMR Study

Abstract

We report on the superconducting (SC) properties of Y${}_2$C${}_3$ with a relatively high transition temperature $T_{\mathrm{c}}=15.7$ K investigated by ${}^{13}$C nuclear-magnetic-resonance (NMR) measurements under a magnetic field. The ${}^{13}$C Knight shift has revealed a significant decrease below $T_{\mathrm{c}}$, suggesting a spin-singlet superconductivity. From an analysis of the temperature dependence of the nuclear spin-lattice relaxation rate $1/T_1$ in the SC state, Y${}_2$C${}_3$ is demonstrated to be a multigap superconductor that exhibits a large gap $2\Delta /k_{\mathrm{B}}{T}_{\mathrm{c}}=5$ at the main band and a small gap $2\Delta /k_{\mathrm{B}}{T}_{\mathrm{c}}=2$ at other bands. These results have revealed that Y${}_2$C${}_3$ is a unique multigap s-wave superconductor similar to MgB${}_2$.

4 pages, 5 figures

Cited by in corpus (3)

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