MIT Researchers Develop Air-Stable Ultrathin Superconductors Using Graphene Encapsulation
A technique to grow niobium diselenide under graphene produces wafer-scale superconducting films that remain stable in air, overcoming a key barrier to scalable quantum devices.
Ultrathin materials like niobium diselenide exhibit superconductivity at low temperatures, making them attractive for quantum circuits because their high kinetic inductance allows for compact, sensitive components. But these atomically thin layers oxidize in seconds when exposed to air, destroying their superconducting properties—a limitation that has kept them confined to inert-atmosphere glove boxes and prevented any practical scale-up. On August 5, MIT researchers reported in Nature a way around this: growing niobium diselenide directly underneath a protective blanket of graphene, producing uniform, wafer-scale films that remain stable in open air.
In the process, called encapsulation epitaxy, a graphene layer is first grown on a substrate using chemical vapor deposition, and then niobium and selenium precursors are introduced to crystallize the superconductor beneath it. Because graphene’s tightly bonded carbon lattice blocks oxygen and water while still permitting electrical contact later, the niobium diselenide is shielded from the moment it forms. This eliminates the narrow window for oxidation that has foiled previous passivation strategies and avoids the need to peel off a protective layer afterward—a workflow that used to limit production to small, inconsistent flakes.
To confirm that the protected material remains functional, the team integrated it into a microwave resonator circuit and measured its performance. The superconductor maintained high kinetic inductance—the property that governs how much magnetic energy it stores—at levels useful for quantum-limited detectors and qubit readout. Since kinetic inductance scales inversely with thickness, a monolayer can achieve values orders of magnitude higher than bulk films, enabling dramatically smaller circuit elements.
The ability to produce wafer-scale, air-stable films addresses one of the chief obstacles to using two-dimensional superconductors in real quantum hardware. Most qubit platforms today rely on patterned aluminum or niobium circuits; incorporating a high-kinetic-inductance monolayer could shrink footprints and reduce cross-talk. The technique could miniaturize quantum computing hardware and enable ultrasensitive detectors, from single-photon counters to bolometers for astronomy. While full integration will require further engineering, having a stable, scalable material is a necessary first step.
The work also highlights the broader utility of graphene as an encapsulation layer. Though only a single atom thick, graphene’s lattice is impermeable to even small molecules, and the MIT team’s approach is not specific to niobium diselenide—other air-sensitive two-dimensional superconductors or topological materials could likely be protected in the same way. The Nature paper (DOI: 10.1038/s41586-026-10865-1) includes atomic-resolution imaging and electronic transport measurements confirming that the graphene-protected film shows the same crystal structure and superconducting transition as pristine, unencapsulated material, indicating that the growth process does not disrupt its intrinsic properties.
What sets this apart is the fusion of synthesis and protection into a single step. The superconductor never encounters ambient air before it is shielded, so it can be patterned into circuits, wire-bonded, and cooled to cryogenic temperatures without degradation. For a field where a few hours of exposure can ruin a device, that is a practical breakthrough—one that moves the conversation from lab demonstrations to the kind of scalable fabrication that quantum technologies need to move beyond bespoke, one-off devices.