Supercurrent in All-Van-der-Waals Josephson Tunnel Junction*

Superconducting quantum circuits have demonstrated tremendous progress over the past decade. However, current state-of-art of superconducting qubits still suffer strongly from dielectric two-level-systems (TLS), a major cause of qubit decoherence. Further advancement of qubit lifetime ultimately requires material and fabrication improvements that reduce TLS loss.
In this work, we construct superconducting quantum devices with van der Waals (vdW) materials and their heterostructures, which feature crystalline layers with atomically precise interface. We fabricate high-quality, all-vdW parallel-plate capacitors and Josephson junctions – two key components in superconducting qubits. We then characterize the dielectric loss of the vdW capacitors and measure the Josephson response of the vdW tunnel junctions. We expect the advent of vdW qubits will enable both high coherence and small form factors.