Faint far-infrared light drives insulator-to-metal transition in magic-angle graphene
Researchers have discovered that magic-angle twisted bilayer graphene can transition from an insulator to a metal when exposed to weak far-infrared radiation. This effect, caused by selective heating of the electronic subsystem, could lead to the development of highly sensitive detectors for the far-infrared spectrum.
Why it matters
This breakthrough offers a new method for detecting difficult-to-capture electromagnetic radiation, with potential applications in medical diagnostics and advanced sensing.
Researchers at the National University of Singapore, the Center for Neurophysics and Neuromorphic Technologies (Moscow), Queen's University (Kingston), HSE University (Moscow), the National Institute for Materials Science (Tsukuba) and the University of Manchester, have shown that magic-angle twisted bilayer graphene (MATBG) can be switched from an insulating to a metallic state by exposure to very weak far-infrared (FIR) radiation, opening a path toward ultrasensitive detectors for one of the least-exploited bands of the electromagnetic spectrum.
MATBG is formed by stacking two graphene sheets with a relative twist of about one degree. At this "magic" angle, the electronic bands narrow dramatically, strengthening interactions between electrons. Under the right gate voltage, these interactions produce a correlated insulator - a fragile collective electronic state in which conduction is strongly suppressed, distinct from an ordinary band insulator.
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