Superconducting quantum interference effect in NbSe₂/NbSe₂ van der Waals junctions

Layered materials with exotic properties, such as superconducting, ferromagnetic, and so on, have attracted broad interest. The advances in van der Waals (vdW) stacking technology have enabled the fabrication of numerous types of junction structures. The dangling-bond-free interface provides an ideal platform to generate and probe various physics phenomena. Typical progress is the realization of vdW Josephson junctions with high supercurrent transparency constructed of two NbSe₂ layers. Here we report the observation of periodic oscillations of the voltage drop across a NbSe₂/NbSe₂ vdW junctions under an in-plane magnetic field. The voltage-drop oscillations come from the interface and the magnitude of the oscillations has a non-monotonic temperature dependence which increases first with increasing temperature. These features make the oscillations different from the modulation of the critical current of a Josephson junction by the magnetic field and the Little-Parks effect. The oscillations are determined to be generated by the quantum interference effect between two superconducting junctions formed between the two NbSe₂ layers.