Full superconducting gap in the doped topological crystalline insulator, Sn$_{0.6}$In$_{0.4}$Te
Full superconducting gap in the doped topological crystalline insulator, Sn$_{0.6}$In$_{0.4}$Te
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DOI：
10.1103/physrevb.88.014523
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发表时间：
2013-07
期刊：
影响因子：
--
通讯作者：
L. P. He;Z. Zhang;J. Pan;X. Hong;S. Zhou;S. Y. Li
中科院分区：
文献类型：
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作者：
L. P. He;Z. Zhang;J. Pan;X. Hong;S. Zhou;S. Y. Li
掺杂拓扑晶体绝缘体 Sn$_{0.6}$In$_{0.4}$Te 超导单晶（$T_c =$4.1 K）的热导率测得低至 50 mK。结果发现，在零磁场下，剩余线性项$\kappa_0/T$可以忽略不计。 $\kappa_0/T$ 在低磁场下表现出缓慢的场依赖性。这些结果表明，超导间隙是无节点的，除非存在方向垂直于热流的点节点。然而，由于 Sn$_{0.6}$In$_{0.4}$Te 具有高对称性 fcc 晶体结构，可以排除此类点节点。因此，我们证明了这种拓扑超导体候选者在整体上具有完全的超导能隙。它很可能是支持表面 Andreev 束缚态的非常规奇宇称 $A_{1u}$ 态。
The thermal conductivity of the doped topological crystalline insulator, Sn$_{0.6}$In$_{0.4}$Te superconducting single crystal with $T_c =$ 4.1 K, was measured down to 50 mK. It is found that the residual linear term $\kappa_0/T$ is negligible in zero magnetic field. The $\kappa_0/T$ shows a slow field dependence at low magnetic field. These results suggest that the superconducting gap is nodeless, unless there exist point nodes with directions perpendicular to the heat current. Due to its high-symmetry fcc crystal structure of Sn$_{0.6}$In$_{0.4}$Te, however, such point nodes can be excluded. Therefore we demonstrate that this topological superconductor candidate has a full superconducting gap in the bulk. It is likely the unconventional odd-parity $A_{1u}$ state which supports a surface Andreev bound state.