How Magical Is Magic-Angle Graphene?
Department of Materials Science and Engineering
The observation of correlated insulating states and unconventional superconductivity on magic-angle twisted bilayer graphene (MATBG) by Cao and Jarillo-Herrero in 2018 has aroused intensive scientific interest in the beautiful moiré-patterned superlattice. The magic angles are a discrete set of angles (with the largest one around 1.1°) at which the twisted bilayer graphene exhibits a unique electronic structure (a nearly flat band) with the vanishing of the Fermi velocity at the Dirac points. Based on such a special platform, strong interlayer electron couplings generate at certain filling states of the flat band and allow the observation of extraordinary physical phenomena. The earliest prediction of the magic angle can date back to 2007, but the magical properties on MATBG have been partially uncovered experimentally only in the last 2 years, including the most recent emergent ferromagnetism with anomalous Hall and quantized anomalous Hall effects. With ongoing endeavors in low-energy physics, we believe that more fascinating phenomena on MATBG and analogues will be discovered in the near future. Meanwhile, great efforts still need to be devoted to elucidating the underlying mechanisms and developing new technologies that could bring these exceptional properties into practical applications.
How Magical Is Magic-Angle Graphene?.
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/2357