Multiband Superconductivity of Heavy Electrons in TlNi2Se2 single crystal

Hangdong Wang; Chiheng Dong; Qianhui Mao; Rajwali Khan; Xi Zhou; Zhenxia Li; Bin Chen; Jinhu Yang; Qiping Su; Minghu Fang

doi:10.1103/PhysRevLett.111.207001

paper

Multiband Superconductivity of Heavy Electrons in TlNi2Se2 single crystal

arXiv:1303.4658 · doi:10.1103/PhysRevLett.111.207001

Abstract

Superconductivity has been first observed in TlNi $_{2}$ Se $_{2}$ at T $_{C}$ =3.7 K and appears to involve heavy electrons with an effective mass $m^{*}$ =14 $\sim$ 20 $m_{b}$ , as inferred from the normal state electronic specific heat and the upper critical field, H_ $C 2$ (T). Although the zero-field electronic specific heat data, $C_{es} (T)$ , in low temperatures (T < 1/4 T $_{C}$ ) can be fitted with a gap BCS model, indicating that TlNi $_{2}$ Se $_{2}$ is a fully gapped superconductor, the two-gap BCS model presents the best fit to all the $C_{es} (T)$ data below $T_{C}$ . It is also found that the electronic specific heat coefficient in the mixed state, $γ_{N} (H)$ , exhibits a \textit{H} $^{1/2}$ behavior, which was also observed in some \textit{s}-wave superconductors, although once considered as a common feature of the \textit{d}-wave superconductors. Anyway, these results indicate that TlNi $_{2}$ Se $_{2}$ , as a non-magnetic analogue of TlFe $_{x}$ Se $_{2}$ superconductor, is a multiband superconductor of heavy electron system.

5 papges, 4 figures

Multiband Superconductivity of Heavy Electrons in TlNi2Se2 single crystal

Abstract

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