Role of interface hybridization on induced superconductivity in 1T$^\prime$-WTe$_2$ and 2H-NbSe$_2$ heterostructures

TL;DR

This study investigates how interface hybridization affects induced superconductivity in 1T'–WTe₂ and 2H–NbSe₂ heterostructures, revealing that strong hybridization can enhance edge state properties despite surface conduction.

Contribution

It introduces a realistic low-energy model with tunable hybridization to analyze edge state physics and proposes an alternative heterostructure geometry for better topological control.

Findings

Strong hybridization enhances local density of states at edges.

Surface conduction can coexist with robust edge states.

Proposed heterostructure geometry enables spatial control of topological phases.

Abstract

Heterostructures between two-dimensional quantum spin Hall insulators (QSHI) 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$^\prime$-WTe$_2$ and s-wave superconductor 2H-NbSe$_2$. We find that even in the presence of strong inter-layer 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 inter-layer hybridization and realize a spatial interface between a regime with a clean QSHI gap and a topological conducting edge state.