Researchers have demonstrated that magic-angle twisted bilayer graphene tuned to half filling of its moiré band converts from an insulator into a metal when exposed to weak long-wavelength light, according to a study published in Nature Communications on August 10, 2026. The optical mechanism uses low-energy photons to heat the material's electronic subsystem, producing a giant resistance change without relying on a persistent photocarrier population.
The device functions as a Moiré bolometer designed for ultrasensitive detection of faint long-wavelength radiation. Weak photons with energies matching the material's flat-band width selectively heat the low-heat-capacity electronic subsystem. This thermal action suppresses the correlated gap in the graphene layers, causing a sharp insulator-to-metal transition and yielding a broadband, low-noise photoresponse.
Device Performance and Physics
The system achieves a voltage responsivity exceeding millivolts per nanowatt of absorbed optical power. Unlike traditional photocarrier detectors, the device's photoresponse stems directly from the extreme sensitivity of its many-body correlated gap to faint electronic heating. The physical operating mechanism acts as a dual to the superconducting hot-electron response: radiation-heated electrons melt the correlated insulator into a metallic state rather than suppressing superconductivity.
This melting transition offers a sharp resistive contrast between insulating and metallic phases while maintaining operational stability in magnetic fields reaching several tesla. The experimental team identified correlated flat-band systems as a practical platform for detecting weak long-wavelength electromagnetic waves.
Research Team and Support
The research was led by equal contributors L. Elesin, A. L. Shilov, and M. Kravtsov alongside co-authors from the National University of Singapore, the Center for Neurophysics and Neuromorphic Technologies, Queen’s University, the Higher School of Economics, the National Institute for Materials Science in Japan, and the University of Manchester. The paper was received by Nature Communications on April 24, 2026, and accepted for publication on July 29, 2026.
Financial support for the study came from the National Research Foundation Singapore under an NRF Fellowship awarded to D. A. Bandurin, the Ministry of Education Singapore, the Royal Society in the UK, JSPS KAKENHI, CREST, JST, and the MEXT World Premier International Research Center Initiative in Japan. The 3D optical component graphics used in the research documentation were provided by Ryo Mizuta Graphics.
