Multi-gap nodeless superconductivity in nickel chalcogenide TlNi2Se2

Abstract

Low-temperature thermal conductivity measurements were performed on single crystals of TlNi${}_2$Se${}_2$, a nickel-chalcogenide heavy-electron superconductor with $T_c$ $\simeq$ 3.7 K. In zero field, the residual electronic contribution at $T$ $\to$ 0 K (${\kappa }_0/T$) was well separated from the total thermal conductivity, which is less than 0.45\% of its normal-state value. Such a tiny residual ${\kappa }_0/T$ is unlikely contributed by the nodal quasiparticles. Nodeless gap structure is supported by the very weak field dependence of ${\kappa }_0(H)/T$ in low magnetic fields. In the whole field range, ${\kappa }_0(H)/T$ exhibits an "$S$"-shape curve, as in the case of nickel pnictides BaNi${}_2$As${}_2$ and SrNi${}_2$P${}_2$. This common feature of nickel-based superconductors can be explained by multiple nodeless superconducting gaps.

5 pages, 3 figures

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• High-temperature superconductivity in iron-based materials
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Cited by in corpus (2)

• ARPES measurements of the superconducting gap of Fe-based superconductors and their implications to the pairing mechanism
• Anomalous Pressure Dependence of the Superconducting Transition Temperature in TlNi${}_2$Se${}_{2-x}$S${}_x$