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Switching off superconductivity solves a decade-old mystery in magic-angle graphene
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Phys.org16d ago
Magic-angle graphene provides evidence for unconventional superconductivity
Researchers have completely suppressed superconductivity in magic-angle graphene by screening interactions between electrons, helping resolve a long-running debate about the origin of the phenomenon.
OriginalInteresting Engineering16d ago
Graphene superconductivity switched off, showing electron interactions drive it
Researchers switched off superconductivity in magic-angle graphene by weakening electron interactions at distances as small as 0.3 nm.
OriginalGraphene-Info16d ago
Switching off superconductivity solves a decade-old mystery in magic-angle graphene
Researchers at the University of Manchester's National Graphene Institute, led by lead author Julien Barrier and corresponding authors Professor Sir Andre Geim and Professor Alexey Berdyugin of the National University of Singapore, together with contributing researchers from the Henry Royce Institute, Washington University in St. Louis, the University of Pennsylvania, the University of Antwerp, and Japan's National Institute for Materials Science, have shown that superconductivity in magic-angle twisted bilayer graphene can be completely suppressed by screening the electrical interactions between its electrons. The result provides strong experimental evidence that electron-electron interactions, rather than atomic vibrations, drive the pairing behind the material's superconductivity, addressing a question that has remained open since magic-angle graphene's superconductivity was first discovered. Magic-angle twisted bilayer graphene, made by stacking two graphene sheets with a rotational offset of about 1.1 degrees, has become one of the most intensely studied quantum materials of the past decade, but the origin of its superconductivity has remained disputed. One camp of theories holds that the pairing is driven by electron-electron interactions, in a manner that could be analogous to high-temperature cuprate superconductors, while another camp favors a more conventional phonon-mediated mechanism, in which lattice vibrations couple electrons into pairs. Previous experiments attempted to settle the question by placing a screening layer near the magic-angle graphene to weaken Coulomb interactions, but those screening layers sat several nanometers away, separated by a dielectric spacer, and only managed to suppress the material's correlated-insulator states while leaving superconductivity largely intact, or shifting its critical temperature by just 2-3%.
OriginalEurekAlert!16d ago
Screening of magic
Switching off superconductivity solves a decade-old mystery in magic-angle graphene
OriginalQuantum Zeitgeist16d ago
Graphene’s Superconductivity Persists Even With Strong Electrostatic Control
Magic-angle twisted bilayer graphene (TBG) exhibits superconductivity, and new research shows it remains stable even with strong electrostatic control.
OriginalGraphene-Info16d ago
Switching off superconductivity solves a decade-old mystery in magic-angle graphene
Researchers at the University of Manchester's National Graphene Institute, led by lead author Julien Barrier and corresponding authors Professor Sir Andre Geim and Professor Alexey Berdyugin of the National University of Singapore, together with contributing researchers from the Henry Royce Institute, Washington University in St. Louis, the University of Pennsylvania, the University of Antwerp, and Japan's National Institute for Materials Science, have shown that superconductivity in magic-angle twisted bilayer graphene can be completely suppressed by screening the electrical interactions between its electrons. The result provides strong experimental evidence that electron-electron interactions, rather than atomic vibrations, drive the pairing behind the material's superconductivity, addressing a question that has remained open since magic-angle graphene's superconductivity was first discovered. Magic-angle twisted bilayer graphene, made by stacking two graphene sheets with a rotational offset of about 1.1 degrees, has become one of the most intensely studied quantum materials of the past decade, but the origin of its superconductivity has remained disputed. One camp of theories holds that the pairing is driven by electron-electron interactions, in a manner that could be analogous to high-temperature cuprate superconductors, while another camp favors a more conventional phonon-mediated mechanism, in which lattice vibrations couple electrons into pairs. Previous experiments attempted to settle the question by placing a screening layer near the magic-angle graphene to weaken Coulomb interactions, but those screening layers sat several nanometers away, separated by a dielectric spacer, and only managed to suppress the material's correlated-insulator states while leaving superconductivity largely intact, or shifting its critical temperature by just 2-3%.
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