Manipulation of Dirac Fermions in Nanochain-Structured GrapheneSupported by the National Key Research and Development Program of China (Grant Nos. 2020YFA0308800 and 2016YFA0202300), the National Natural Science Foundation of China (Grant Nos. 11974045 and 61888102), Chinese Academy of Sciences (Grant No. XDB30000000), Beijing Institute of Technology Research Fund Program for Young Scholars (Grant No. 3050011181909), and China Postdoctoral Science Foundation (Grant

Abstract

Graphene has afforded an ideal 2D platform for investigating a rich and fascinating behavior of Dirac fermions. Here, we develop a theoretical mechanism for manipulating the Dirac fermions in graphene, such as from type-I to type-II and type-III, by a top-down nanopatterning approach. We demonstrate that by selective chemical adsorption to pattern the 2D graphene into coupled 1D armchair chains (ACs), the intrinsic isotropic upright Dirac cone becomes anisotropic and strongly tilted. Based on model analyses and first-principles calculations, we show that both the shape and tilt of Dirac cone can be tuned by the species of chemisorption, e.g., halogen vs hydrogen, which modifies the strength of inter-AC coupling. Furthermore, the topological edge states and transport properties of the engineered Dirac fermions are investigated. Our work sheds lights on understanding the Dirac fermions in a nanopatterned graphene platform, and provides guidance for designing nanostructures with novel functionality.