论文标题
稳定石墨烯/过渡金属二北元异化异源结构中样品范围的kekulé订单
Stabilizing sample-wide Kekulé orders in graphene/transition metal dichalcogenide heterostructures
论文作者
论文摘要
Kekulé相是石墨烯中的PEIERLS样晶格扭曲，预计将在石墨烯（1-8）以外的新型电子状态（1-8）中占据。尽管在石墨烯中通过在高磁场（9-11）或Adatom超级晶格（12-15）引入电子电子相互作用来实现Kekulé相，但获得实验中的大面积石墨烯kekulé相仍然是一个极其挑战。在这里，我们证明了石墨烯中样品范围的kekulé扭曲可以通过使用过渡金属二核苷（TMD）作为底物稳定，作为底物和诱导的kekulé订单，在整个石墨烯/TMDS异质结构中具有不同的扭曲角度。异质结构的相应结构提供了周期性的散射中心，这些中心破坏了石墨烯中两个山谷的地石墨烯的翻译对称性，这将石墨烯朝向全球kekulé密度波阶段。出乎意料的是，在每个石墨烯/TMD异质结构中直接成像在各种能量下稳定的三个不同的kekulé键纹理。我们的结果揭示了石墨烯中电子特性对支持底物的意外敏感性，并为设计石墨烯/TMD异质结构中的新阶段提供了有吸引力的途径。
Kekulé phases are Peierls-like lattice distortions in graphene that are predicted to host novel electronic states beyond graphene (1-8). Although the Kekulé phases are realized in graphene through introducing electron-electron interactions at high magnetic fields (9-11) or adatom superlattices (12-15), it is still an extremely challenge to obtain large-area graphene Kekulé phases in experiment. Here we demonstrate that sample-wide Kekulé distortions in graphene can be stabilized by using transition metal dichalcogenides (TMDs) as substrates and the induced Kekulé orders are quite robust in the whole graphene/TMDs heterostructures with different twist angles. The commensurate structures of the heterostructures provide periodic scattering centers that break the translational symmetry of graphene and couple electrons of the two valleys in graphene, which tips the graphene toward global Kekulé density wave phases. Unexpectedly, three distinct Kekulé bond textures stabilized at various energies are directly imaged in every graphene/TMDs heterostructure. Our results reveal an unexpected sensitivity of electronic properties in graphene to the supporting substrates and provide an attractive route toward designing novel phases in graphene/TMDs heterostructures.
