Heterostructures between two-dimensional quantum spin Hall insulators (QSHIs) and superconducting materials can allow for the presence of Majorana fermions at their conducting edge states. Although a strong interface hybridization helps induce a reasonable superconducting gap on the topological material, the hybridization can modify the material’s electronic structure. In this work, we utilize a realistic low-energy model with tunable interlayer hybridization to study the edge-state physics in a heterostructure between monolayer quantum spin Hall insulator 1T ′-WTe2 and s-wave superconductor 2H-NbSe2. We find that even in the presence of strong interlayer hybridization that renders the surface to become conducting, the edge state shows a significantly enhanced local density of states and induced superconductivity compared to the surface. We provide an alternate heterostructure geometry that can utilize the strong interlayer hybridization and realize a spatial interface between a regime with a clean QSHI gap and a topological conducting edge state.

 

References:

A. Das, B. Weber, & S. Mukherjee (2023). Role of interface hybridization on induced superconductivity in 1 T′-WTe 2 and 2 H-NbSe2 heterostructures. Physical Review B, 108(7), 075410.

Tao,  et al. "Multiband superconductivity in strongly hybridized 1T′-WTe 2/NbSe 2 heterostructures." Physical Review B 105.9 (2022):094512.