Competing Gap Opening Mechanisms of Monolayer Graphene and Graphene Nanoribbons on Strong Topological Insulators
Competing Gap Opening Mechanisms of Monolayer Graphene and Graphene Nanoribbons on Strong Topological Insulators
复制标题
强拓扑绝缘体上单层石墨烯和石墨烯纳米带的竞争间隙打开机制
DOI：
10.1021/acs.nanolett.6b05354
复制
发表时间：
2017-07-01
期刊：
影响因子：
10.8
通讯作者：
Zhang, Zhenyu
中科院分区：
文献类型：
--
作者：
Lin, Zhuonan;Qin, Wei;Zhang, Zhenyu
Graphene is a promising material for designing next-generation electronic and valleytronic devices, which often demand the opening of a bandgap in the otherwise gapless pristine graphene. To date, several conceptually different mechanisms have been extensively exploited to induce., bandgaps in graphene, including spin-orbit coupling and inversion symmetry breaking for monolayer graphene, and quantum confinement for graphene nanoribbons (GNRs). Here, we present a multiscale study of the competing gap opening mechanisms in a graphene overlayer and GNRs proximity-coupled to topological insulators (TIs). We obtain sizable graphene bandgaps even without inversion symmetry breaking and identify the Kekule lattice distortions caused by the TI substrates to be the dominant gap opening mechanism. Furthermore, Kekule distorted armchair GNRs display intriguing non monotonous gap dependence on the nanoribbon width, resulting from the coexistence of quantum confinement, edge passivation, and Kekule distortions. The present study offers viable new approaches for tunable bandgap engineering in graphene and GNRs.
