Invited Paper SP+AS+BI+NS+SS-WeA1
Majorana Mode in Vortex core of Bi₂Te₃/NbSe₂Topological Insulator-Superconductor Heterostructure

Wednesday, November 12, 2014, 2:20 pm, Room 312

Majorana fermions have been intensively studied in recent years for their importance to both fundamental science and potential applications in topological quantum computing^1,2. Majorana fermions are predicted to exist in a vortex core of superconducting topological insulators³. However, they are extremely difficult to be distinguished experimentally from other quasiparticle states for the tiny energy difference between Majorana fermions and these states, which is beyond the energy resolution of most available techniques. Here, we overcome the problem by systematically investigating the spatial profile of the Majorana mode and the bound quasiparticle states within a vortex in Bi₂Te₃/NbSe₂⁴ by using in situ ultra-low temperature STM/STS. While the zero bias peak in local conductance splits right off the vortex center in conventional superconductors, it splits off at a finite distance ~20nm away from the vortex center in Bi₂Te₃/NbSe₂, primarily due to the Majorana fermion zero mode. While the Majorana mode is destroyed by reducing the distance between vortices, the zero bias peak splits as a conventional superconductor again. This work provides strong evidences of Majorana fermions and also suggests a possible route to manipulating them.

References:

1. J. Alicea, Rep. Prog. Phys.75, 076501 (2012).

2. C. W. J. Beenakker, Annu. Rev. Con. Mat. Phys. 4, 113 (2013).

3. L. Fu, C. L. Kane, Phys. Rev. Lett. 100, 096407 (2008).

4. M. X. Wang et al., Science 336, 52 (2012)

* In cooperation with Jin-Peng Xu, Mei-Xiao Wang, Zhi Long Liu, Jian-Feng Ge, Xiaojun Yang, Canhua Liu, Zhu An Xu, Dandan Guan, Chun Lei Gao, Dong Qian, Ying Liu, Qiang-Hua Wang, Fu-Chun Zhang, Qi-Kun Xue