Long-range pairing in monolayer NbSe2 facilitates the emergence of topological superconducting states

Abstract

Abstract The paper systematically study topological superconducting (TSC) phases in monolayer NbSe2 by constructing the hybrid paring tight-binding model of mixing on-site s-wave pairing (ps ) and long-range pairing (p A1) for the first time. We observe rich phases with both fixed and sensitive Chern numbers (CNs) depending on the chemical potential (μ) and out-of-plane magnetic field (Vz ). As p A1 increases, the TSC phase manifests matching and mismatching features according to whether the CNs match with the number of topological edge states (TESs). Strikingly, the introduction of long-range pairing significantly reduces the critical Vz to form TSC phases compared with the pure on-site s-wave paring. Moreover, the TSC phases can be modulated even at Vz = 0 under appropriate μ and p A1, which is identified by the robust TESs of ribbons. Additionally, the long-range pairing influences the hybridization of bulk and edge states, resulting in a matching/mismatching bulk-boundary correspondence with localized/oscillating TESs on the ribbons. Our findings are helpful for realizing TSC states through compressive strain experimentally to strengthen long-range pairings, as well as designing and regulating TSC materials.