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Observation of superconductivity induced by a point contact on 3D Dirac semimetal Cd3As2 crystals

Abstract

Three-dimensional (3D) Dirac semimetals, which possess 3D linear dispersion in the electronic structure as a bulk analogue of graphene, have lately generated widespread interest in both materials science and condensed matter physics1,2. Recently, crystalline Cd3As2 has been proposed and proved to be a 3D Dirac semimetal that can survive in the atmosphere3,4,5,6,7,8,9. Here, by using point contact spectroscopy measurements, we observe exotic superconductivity around the point contact region on the surface of Cd3As2 crystals. The zero-bias conductance peak (ZBCP) and double conductance peaks (DCPs) symmetric around zero bias suggest p-wave-like unconventional superconductivity. Considering the topological properties of 3D Dirac semimetals, our findings may indicate that Cd3As2 crystals under certain conditions could be topological superconductors10,11,12,13, which are predicted to support Majorana zero modes or gapless Majorana edge/surface modes in the boundary depending on the dimensionality of the material14,15,16,17.

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Figure 1: Transport measurements of Cd3As2 (S1).
Figure 2: Superconducting features in S1 at a PC resistance of 7.5 Ω.
Figure 3: Transport results of another Cd3As2 sample (S2).
Figure 4: Topological phase diagram for superconducting Cd3As2.

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Acknowledgements

We acknowledge C. Zhang, F. Yang, Y. Xing and Y. Liu for help with experiments. This work was financially supported by the National Basic Research Program of China (Grant Nos. 2013CB934600, 2015CB921102, 2012CB921300, 2012CB927400), the National Natural Science Foundation of China (Nos. 11222434, 11174007, 11534001, 11574008), and the Research Fund for the Doctoral Program of Higher Education (RFDP) of China.

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J.Wang and J.Wei conceived the experiments. He Wang, Huichao Wang and W.Y. carried out transport measurements. Haiwen Liu, X.-J.L. and X.C.X. performed the theoretical interpretation. Hong Lu and S.J. grew the crystals.

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Correspondence to Xiong-Jun Liu, Jian Wei or Jian Wang.

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The authors declare no competing financial interests.

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Wang, H., Wang, H., Liu, H. et al. Observation of superconductivity induced by a point contact on 3D Dirac semimetal Cd3As2 crystals. Nature Mater 15, 38–42 (2016). https://doi.org/10.1038/nmat4456

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