Artificial topological superconductor by the proximity effect

Jin Peng Xu, Canhua Liu, Mei Xiao Wang, Jianfeng Ge, Zhi Long Liu, Xiaojun Yang, Yan Chen, Ying Liu, Zhu An Xu, Chun Lei Gao, Dong Qian, Fu Chun Zhang, Jin Feng Jia

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Abstract

Topological superconductors (TSCs), featuring fully gapped bulk and gapless surface states as well as Majorana fermions, have potential applications in fault-tolerant topological quantum computing. Because TSCs are very rare in nature, an alternative way to study the TSC is to artificially introduce superconductivity into the surface states of a topological insulator through the proximity effect [X.L. Qi, T.L. Hughse, S. Raghu, and S.C. Zhang, Phys. Rev. Lett. 102, 187001 (2009); L. Fu and C.L. Kane, Phys. Rev. Lett. 100, 096407 (2008); J. Alicea, Rep. Prog. Phys. 75, 076501 (2012); C.W.J. Beenakker, Annu. Rev. Condens. Matter Phys. 4, 113 (2013)]. Here we report the experimental realization of the proximity effect-induced TSC in Bi2Te3 thin films grown on a NbSe2 substrate, as demonstrated by the density of states probed using scanning tunneling spectroscopy. We observed Abrikosov vortices and Andreev lower energy bound states on the surface of the topological insulator, with the superconducting coherence length depending on the film thickness and the magnetic field. These results also indicate that the topological surface states of Bi2Te3 thin films are superconducting and, thus, that the Bi2Te3/NbSe2 is an artificial TSC. The feasibility of fabricating a TSC with an individual Majorana fermion bound to a superconducting vortex for topological quantum computing is discussed.

Original languageEnglish (US)
Article number217001
JournalPhysical Review Letters
Volume112
Issue number21
DOIs
StatePublished - May 30 2014

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Xu, J. P., Liu, C., Wang, M. X., Ge, J., Liu, Z. L., Yang, X., Chen, Y., Liu, Y., Xu, Z. A., Gao, C. L., Qian, D., Zhang, F. C., & Jia, J. F. (2014). Artificial topological superconductor by the proximity effect. Physical Review Letters, 112(21), [217001]. https://doi.org/10.1103/PhysRevLett.112.217001