Year: 2026
Type: article
Abstract: In the presence of a magnetic field, electronic states of moiré quantum materials develop a Hofstadter spectrum that provides a distinctive setting for studying the interplay between band topology and strong electron-electron interaction. Using scanning tunneling microscopy, we studied Hofstadter's states in bilayer graphene aligned with hexagonal boron nitride and directly visualized the formation of interaction-driven symmetry breaking Chern insulators. Our measurements revealed the formation of phases that double, triple, or quadruple the moiré unit cell at fractional filling of the Hofstadter bands as well as states with complex intra-unit cell wave functions. We visualized two distinct quantum phenomena in different Chern states, including quantum melting driven by the appearance and proliferation of topological defects and a quantum transition co-occurring with phase competition and separation.
Source: Science
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Simons Foundation, Gordon and Betty Moore Foundation, Princeton Center for Complex Materials, Materials Research Science and Engineering Center, Harvard University, Multidisciplinary University Research Initiative, Office of Naval Research, Division of Materials Research, Army Research Office
Awards: PROBING CORRELATED SUPERCONDUCTORS AND THEIR PHASE TRANSITIONS ON THE NANOMETER SCALE, G1746067696, G1877134453, G2174132073, G222768804, Ali Yazdani Experimental Investigator Award, G3603580073, G3715997057, Visualizing Novel Electronic Orders in Bilayer Graphene Systems, G4507533284, Predicting Zero-Magnetic-Field Fractional Topological States in Twisted Graphene Systems, G58802512, G6536552022, G6621819458, Princeton Center for Complex Materials, G7320067581, G7452299184, PROBING CORRELATED SUPERCONDUCTORS AND THEIR PHASE TRANSITIONS ON THE NANOMETER SCALE
OpenAlex ID: W7165778220