Recent progress in preparing well controlled 2D van der Waals heterojunctions has opened up a new frontier in materials physics. In this paper 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 behavior 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.
@article{arxiv.1403.0496,
title = {Origin of band gaps in graphene on hexagonal boron nitride},
author = {Jeil Jung and Ashley DaSilva and Allan H. MacDonald and Shaffique Adam},
journal= {arXiv preprint arXiv:1403.0496},
year = {2015}
}
Comments
16 pages 15 figures. This version corrects minor numerical errors