title: Robust 2D topological insulators in van der Waals heterostructures.
abstract: We predict a family of robust two-dimensional (2D) topological insulators in van der Waals heterostructures comprising graphene and chalcogenides BiTeX (X = Cl, Br, and I). The layered structures of both constituent materials produce a naturally smooth interface that is conducive to proximity-induced topological states. First-principles calculations reveal intrinsic topologically nontrivial bulk energy gaps as large as 70-80 meV, which can be further enhanced up to 120 meV by compression. The strong spin-orbit coupling in BiTeX has a significant influence on the graphene Dirac states, resulting in the topologically nontrivial band structure, which is confirmed by calculated nontrivial Z2 index and an explicit demonstration of metallic edge states. Such heterostructures offer a unique Dirac transport system that combines the 2D Dirac states from graphene and 1D Dirac edge states from the topological insulator, and it offers ideas for innovative device designs.
authors.affiliation: Bremen Center for Computational Materials Science, University of Bremen , Am Falturm 1, 28359 Bremen, Germany.
authors.forename: Liangzhi
authors.initials: L
authors.lastname: Kou
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Wu
authors.forename: Claudia
authors.initials: C
authors.lastname: Felser
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenheim
authors.forename: Changfeng
authors.initials: C
authors.lastname: Chen
authors.forename: Binghai
authors.initials: B
authors.lastname: Yan
keywords: Dirac Transport; Graphene; topological insulator; van der Waals Heterostructures