Stacking two layers of graphene on top of each other—and adding a slight “twist” between them—produces a material that exhibits a range of remarkable electronic phenomena, from the unrestricted flow of superconductors to the impeded transport of strange metals. Physicists can explore this rich electronic landscape just by altering the relative orientation between the two sheets of this so-called twisted bilayer graphene (TBG), creating a whole new field of study called twistronics.
Such intriguing behavior, first observed in 2018, is thought to derive from a strong coupling between electrons and phonons—the quantized vibrational motions of a crystal lattice. But efforts to understand this interaction have been hampered by the lack of experimental tools for directly probing the phonons in TBG. Now an international team of researchers has shown theoretically how a novel type of microscope could offer a way to study the electron–phonon coupling in TBG and other twisted 2D lattices—known collectively as moiré systems [1]. Such investigations could help unravel the origin of superconductivity in TBG while also informing the development of novel devices such as superconducting switches (see Trend: Bilayer Graphene’s Wicked, Twisted Road).
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