Universal transport signatures of Ising superconductivity in two-dimensional van der Waals heterostructures

Анотація

Understanding transport signatures of superconductivity in low-dimensional materials is essential for the development of superconducting electronics and quantum devices. We theoretically investigate quasiparticle transport in a graphene-2D transition-metal dichalcogenide superconductor–graphene junction within a minimal effective Bogoliubov–de Gennes framework including intrinsic Ising spin-orbit coupling and an out-of-plane magnetic field. Current-voltage characteristics and differential conductance of the normal metal–superconductor normal metal structure are calculated using a scattering-matrix approach. We demonstrate that intrinsic Ising spin-orbit coupling suppresses sharp gap-edge conductance resonances and produces smoother spectroscopic features through spin splitting of the quasiparticle spectrum, whereas a perpendicular magnetic field partially weakens this Ising protection via Zeeman coupling. The calculated finite-temperature conductance spectra qualitatively reproduce tunneling characteristics reported for monolayer NbSe2 and related transition-metal dichalcogenide superconductors. The proposed minimal model identifies universal transport signatures of Ising superconductivity that are expected to apply to a broad class of two-dimensional non-centrosymmetric superconductors.