Multiple flat bands and topological Hofstadter butterfly in twisted bilayer graphene close to the second magic angle
Xiaobo Lu, Biao Lian, Gaurav Chaudhary, B. A. Piot, Giulio Romagnoli, Kenji Watanabe, Takashi Taniguchi, Martino Poggio, A. H. MacDonald, B. Andrei Bernevig, Dmitri K. Efetov
Abstract
∼ 0.5°, which cannot be explained without considering electron-election interactions. With high magnetic field magnetotransport measurements we further reveal an energetically unbound Hofstadter butterfly spectrum in which continuously extended quantized Landau level gaps cross all trivial band gaps. The connected Hofstadter butterfly strongly evidences the topologically nontrivial textures of the multiple moiré bands. Overall, our work provides a perspective for understanding the quantum phases in tBLG and the fractal Hofstadter spectra of multiple topological bands.
Topics & Concepts
SuperlatticeMagic angleBilayer graphenePhysicsCondensed matter physicsLandau quantizationTopological insulatorQuantum Hall effectMAGIC (telescope)Magnetic fieldSpectral lineTopology (electrical circuits)GrapheneQuantum mechanicsMathematicsCombinatoricsGraphene research and applicationsTopological Materials and PhenomenaQuantum and electron transport phenomena