Twisted graphene and synthetic diamond unlock a new way to switch superconductivity on and off — a discovery that could reshape the foundations of quantum computing

Researchers have identified a method to control superconductivity by pairing twisted bilayer graphene with a synthetic diamond-like substrate. This approach allows scientists to turn the zero-resistance state on and off through adjustments in the material’s surroundings. The finding opens pathways for advanced electronics and quantum technologies that operate with greater precision and efficiency.

The Material at the Center of the Advance

Physicists constructed twisted bilayer graphene by stacking two single-atom-thick sheets of carbon and rotating one relative to the other at a precise angle. This configuration creates unique electronic properties, including the emergence of superconductivity at low temperatures.

When placed near strontium titanate, the system permitted detailed observation of electron behavior. The substrate influenced how electrons interacted, providing a handle for external control over the superconducting state.

Controlling Electron Pairing

In superconductors, electrons form pairs that move without scattering, enabling resistance-free current flow. The research team tuned the environment around the twisted graphene to modulate the strength of these interactions.

Adjustments via the strontium titanate substrate strengthened or weakened the pairing. This environmental tuning effectively switched superconductivity within the same sample, demonstrating a direct link between surroundings and quantum behavior.

Observations That Challenge Expectations

The team noted an unexpected outcome during experiments. Increasing certain interactions led to a reduction in superconductivity rather than an enhancement. This pattern departs from the behavior seen in many conventional superconductors.

Such results suggest that the mechanisms in twisted graphene systems operate differently. The findings highlight the value of exploring these materials to uncover new principles governing electron correlations.

Implications for Quantum Technologies

Superconductivity holds promise for quantum computing, where stable qubits and low-noise operations are essential. The ability to switch the property on and off could support more flexible device designs and improved coherence times.

Broader applications may extend to energy-efficient electronics and power systems. Continued study of these hybrid structures aims to refine control techniques and extend the temperature range for practical use.

Next Steps in the Research

Scientists plan to examine additional interaction types and test the approach across varied material combinations. The work, published in Nature Physics, establishes a foundation for deeper investigation into unconventional superconductivity.

Led by Chun Ning Lau at The Ohio State University, the effort involved collaborators from multiple institutions. Further experiments will address remaining questions about the underlying physics.