title: Origin of band gaps in graphene on hexagonal boron nitride.
abstract: Recent progress in preparing well-controlled two-dimensional van der Waals heterojunctions has opened up a new frontier in materials physics. Here we address the intriguing energy gaps that are sometimes observed when a graphene sheet is placed on a hexagonal boron nitride substrate, demonstrating that they are produced by an interesting interplay between structural and electronic properties, including electronic many-body exchange interactions. Our theory is able to explain the observed gap behaviour by accounting first for the structural relaxation of graphene's carbon atoms when placed on a boron nitride substrate, and then for the influence of the substrate on low-energy π-electrons located at relaxed carbon atom sites. The methods we employ can be applied to many other van der Waals heterojunctions.
authors.affiliation: Graphene Research Centre, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore.
authors.forename: Jeil
authors.identifier: 0000000325230905
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600 Austin, Austin, Texas 78712-1192, USA.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: DaSilva
authors.affiliation: Department of Physics, The University of Texas at Austin, 2515 Speedway, C1600 Austin, Austin, Texas 78712-1192, USA.
authors.forename: Allan H
authors.initials: AH
authors.lastname: MacDonald
authors.affiliation: 1] Graphene Research Centre, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore [2] Yale-NUS College, 6 College Avenue East, Singapore 138614, Singapore.
authors.forename: Shaffique
authors.identifier: 0000000230959920
authors.initials: S
authors.lastname: Adam