Proximity-effect-induced superconductivity in a van der Waals heterostructure consisting of a magnetic topological insulator and a conventional superconductor

Nontrivial topological superconductivity has received enormous attention due to its potential applications in topological quantum computing. The intrinsic issue concerning the correlation between a topological insulator and a superconductor is, however, still widely open. Here, we systemically report an emergent superconductivity in a cross junction composed of a magnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ and a conventional superconductor ${\mathrm{NbSe}}_{2}$. Remarkably, the interface indicates the existence of a reduced superconductivity at the surface of ${\mathrm{NbSe}}_{2}$ and a proximity-effect-induced superconductivity at the surface of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$. Furthermore, the in-plane angular-dependent magnetoresistance measurements unveil distinctive features indicative of unconventional pairing symmetry in these superconducting gaps. Our findings extend our views and ideas of topological superconductivity in the superconducting heterostructures with time-reversal symmetry breaking, offering an exciting opportunity to elucidate the cooperative effects on the surface state of a topological insulator aligning a superconductor.