Department of Physics, Stanford University, Stanford, California 94305, USA.
Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Nat Commun. 2017 May 15;8:15418. doi: 10.1038/ncomms15418.
Ballistic electrons in solids can have mean free paths far larger than the smallest features patterned by lithography. This has allowed development and study of solid-state electron-optical devices such as beam splitters and quantum point contacts, which have informed our understanding of electron flow and interactions. Recently, high-mobility graphene has emerged as an ideal two-dimensional semimetal that hosts unique chiral electron-optical effects due to its honeycomb crystalline lattice. However, this chiral transport prevents the simple use of electrostatic gates to define electron-optical devices in graphene. Here we present a method of creating highly collimated electron beams in graphene based on collinear pairs of slits, with absorptive sidewalls between the slits. By this method, we achieve beams with angular width 18° or narrower, and transmission matching classical ballistic predictions.
固体中的弹道电子的平均自由程远大于光刻所能形成的最小特征尺寸。这使得能够开发和研究诸如分束器和量子点接触之类的固态电子光学器件，从而加深了我们对电子流动和相互作用的理解。最近，高迁移率的石墨烯作为一种理想的二维半导体金属，由于其蜂窝状晶格而具有独特的手性电子光学效应。然而，这种手性输运阻止了我们使用简单的静电门在石墨烯中定义电子光学器件。在这里，我们提出了一种在基于共线狭缝对的石墨烯中产生高度准直电子束的方法，狭缝之间具有吸收性侧壁。通过这种方法，我们实现了具有 18°或更窄角宽的光束，并且传输与经典弹道预测相匹配。
