Abstract:

Topological superconductors have attracted increasing attentions for the purpose of the quantum computation, because the character of supporting topological qubits are immune to quantum decoherence and can be manipulated by braiding operation. Since the topological superconducting state is rather rare in the intrinsic topological superconductors, most of experimental efforts focus on inducing topological superconductors by the proximity effect in superconductor (SC)/topological insulator (TI) heterostructures. Fu and Kane have theoretically proposed that the topological superconductivity can be obtained by inducing an s-wave superconducting gap into TIs. After that, a lot of experimental progress has been made in different systems. In the first part of this review, we introduce the heterostructure of threedimensional (3D) TI Bi₂Se₃ and Bi₂Te₃ on s-wave SC NbSe₂ and d-wave SC Bi₂Sr₂CaCu₂O_8+δ, topological crystalline insulator Sn_1−xPb_xTe on Pb, two-dimensional (2D) TI WTe₂ on NbSe₂, and TiBiSe₂ on Pb. In the second part, the TI-based Josephson junctions are reviewed by introducing various experiments, including the Josephson junctions with TI barrier layers based on the Fu-Kane mode, and the superconducting quantum interference devices by TI based Josephson junctions.

Key words: proximity effect, topological superconductor, heterostructure, Josephson junction