Emergent superconductivity and non-reciprocal transport at the interface of the Dirac semimetal (ZrTe₂) and an antiferromagnet (FeTe)

Superconductivity (SC) in Dirac semimetals (DSM) has attracted significant interest in recent years because of several exciting theoretical predictions, including topological superconductivity, Majorana modes, unconventional pairing, and monopole superconductivity. Experiments seeking to observe these phenomena have largely centered on the canonical Dirac semimetal, Cd₃As₂, via mesoscopic point contacts or pressure in bulk crystals and patterned superconducting contacts. Despite experimental efforts, the diverse phenomena predicted by theory are yet to be definitively observed, perhaps due to the limitations of the materials and device geometry used. This motivates the search for new materials platforms where SC can be realized in a DSM in a well-controlled geometry at conveniently accessible temperatures (T ≥ 4.2 K).

Here we report the realization of a wafer-scale, van der Waals DSM/antiferromagnet heterostructure (ZrTe₂/FeTe) that can serve as an influential platform for pursuing exotic SC states in bulk Dirac bands. These hybrids show robust, emergent 2D SC coexisting with the DSM bulk bands. We observe striking non-reciprocal transport (magneto-chiral anisotropy) in the transition region from the normal to superconducting state and the superconducting diode effect in the fully superconducting state. Remarkably, when these hybrids are capped with a 2D van der Waals ferromagnet (CrTe₂), thus breaking time-reversal symmetry far from the interface, the efficiency of the superconducting diode effect is greatly enhanced to ~30%, comparable to the record values reported in the literature. With strong spin-orbit coupling in ZrTe₂, these epitaxial heterostructures provide a new platform for systematic manipulation to explore the interplay of topology, magnetism, and superconductivity.