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Schlagwörter:
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Zusammenfassung:
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.