Journal Article

Massive Dirac Fermions and Hofstadter Butterfly in a van der Waals Heterostructure

Koshino, M., Moon, P., Hunt, B., Young, A. F., Sanchez-Yamagishi, J. D., Watanabe, K., LeRoy, B. J., Taniguchi, T., Ashoori, R. C., Jarillo-Herrero, P., Yankowitz, M.

2013

Overview

van der Waals heterostructures constitute a new class of artificial materials formed by stacking atomically thin planar crystals. We demonstrated band structure engineering in a van der Waals heterostructure composed of a monolayer graphene flake coupled to a rotationally aligned hexagonal boron nitride substrate. The spatially varying interlayer atomic registry results in both a local breaking of the carbon sublattice symmetry and a long-range moiré superlattice potential in the graphene. In our samples, this interplay between short-and long-wavelength effects resulted in a band structure described by isolated superlattice minibands and an unexpectedly large band gap at charge neutrality. This picture is confirmed by our observation of fractional quantum Hall states at ±5/3 filling and features associated with the Hofstadter butterfly at ultrahigh magnetic fields.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Artificial satellites / Atoms & subatomic particles / Banded structure / Boron / Boron nitride / Butterflies / Butterflies & moths / Capacitance / Carbon / combs (social insects) / Conceptual lattices / Condensed matter: electronic structure, electrical, magnetic, and optical properties / Construction / Crystals / Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems / Electronic structure / Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures / Electronic transport in multilayers, nanoscale materials and structures / Electronics / Electrons / Exact sciences and technology / Grants / Graphene / Heterostructures / Landau levels / Magnetic fields / Materials science / nitrogen / Physics / Semiconductors / silicon / Superlattices / Thin films and multilayers / van der Waals forces / wavelengths