论文标题
扭曲双层石墨烯中局部电子结构的纳米 - 光电图
Nano-photocurrent mapping of local electronic structure in twisted bilayer graphene
论文作者
论文摘要
我们报告了扭曲的双层石墨烯（TBG）的纳米 - 光电流和红外纳米镜检查研究，可在短至20 nm的长度尺度上访问局部电子现象。我们表明，光电流变化的符号在跟踪TBG状态的局部超晶格密度的载体密度上发生了变化。我们使用此属性来识别局部光 - 心理效应不同局部扭转角的域。与光电流研究一致，红外纳米成像实验揭示了以扭曲角度依赖性的频带间跃迁为主的光传导性特征。我们的结果为映射TBG的电子结构提供了一种快速，可靠的方法，并建议可以将类似的方法广泛应用于其他范德华异质结构中Moiré超晶格的探针电子不均匀性。
We report a combined nano-photocurrent and infrared nanoscopy study of twisted bilayer graphene (TBG) enabling access to the local electronic phenomena at length scales as short as 20 nm. We show that the photocurrent changes sign at carrier densities tracking the local superlattice density of states of TBG. We use this property to identify domains of varying local twist angle by local photo-thermoelectric effect. Consistent with the photocurrent study, infrared nano-imaging experiments reveal optical conductivity features dominated by twist-angle dependent interband transitions. Our results provide a fast and robust method for mapping the electronic structure of TBG and suggest that similar methods can be broadly applied to probe electronic inhomogeneities of moiré superlattices in other van der Waals heterostructures.
