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arXiv · 2303.14659

Refined Majorana phase diagram in topological insulator-superconductor hybrid system

Xin Yue·Guo-Jian Qiao·C. P. Sun
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Abstract

The edge state of the topological insulator coupled to a superconductor system is able to simulate the Majorana fermion in zero energy mode since the Kitaev-type pairing is induced by exchanging quasi-excitations in electron tunneling. However, the present study has revealed that this physical simulation is not valid for a larger surface gap, which is the energy gap of the insulator's surface states. To address this issue, a refined pairing term that depends on the surface gap has been obtained as a second-order effect of the proximity effect, whereas the lowest order produces a constant pairing strength. By carefully considering the dependence of pairing strength on the surface gap, the Majorana phase diagram is re-achieved and a significant difference from previous work is observed, where the pairing strength was assumed to be independent of the surface gap and resulted in a conical phase boundary.

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Xin Yue, Guo-Jian Qiao, C. P. Sun. 2023-03-26. Refined Majorana phase diagram in topological insulator-superconductor hybrid system. https://doi.org/10.1103/physrevb.108.195405

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