Electronic tattoos (e-tattoos) are an extremely thin form of wearable electronics. They are lightweight and soft, which allows them to be intimately mounted on human skin for noninvasive, high-fidelity sensing. During the operation of e-tattoos, they are constantly exposed to external mechanical inputs such as bending, twisting, pressing, and cutting, which may cause mechanical damage and lead to malfunction. Now, researchers have demonstrated a self-healing silk e-tattoo that shows high sensitivity to multiple stimuli, including strain, humidity, and temperature based on a unique graphene, silk fibroin, Ca2+ combination.
Materials with flat electronic bands often exhibit exotic quantum phenomena owing to strong correlations. An isolated low-energy flat band can be induced in bilayer graphene by simply rotating the layers by 1.1°, resulting in the appearance of gate-tunable superconducting and correlated insulating phases. In this study, we demonstrate that in addition to the twist angle, the interlayer coupling can be varied to precisely tune these phases. We induce superconductivity at a twist angle larger than 1.1°—in which correlated phases are otherwise absent—by varying the interlayer spacing with hydrostatic pressure. Our low-disorder devices reveal details about the superconducting phase diagram and its relationship to the nearby insulator. Our results demonstrate twisted bilayer graphene to be a distinctively tunable platform for exploring correlated states.
Combining an atomically thin graphene and a boron nitride layer at a slightly rotated angle changes their electrical properties. Physicists have now shown for the first time the combination with a third layer can result in new material properties also in a three-layer sandwich of carbon and boron nitride. This significantly increases the number of potential synthetic materials.