With the advent of high mobility encapsulated graphene devices, new electronic components ruled by Dirac fermions optics have been envisioned and realized. The main building blocks of electron-optics devices are gate-defined p–n junctions, which guide, transmit and refract graphene charge carriers, just like prisms and lenses in optics. The reflection and transmission are governed by the p–n junction smoothness, a parameter difficult to tune in conventional devices. Here we create p–n junctions in graphene, using the polarized tip of a scanning gate microscope, yielding Fabry–Pérot interference fringes in the device resistance. We control the p–n junctions smoothness using the tip-to-graphene distance, and show increased interference contrast using smoother potential barriers. Extensive tight-binding simulations reveal that smooth potential barriers induce a pronounced quasi-confinement of Dirac fermions below the tip, yielding enhanced interference contrast. On the opposite, sh...

中文翻译：

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通过潜在的光滑度工程优化Dirac费米子准约束

随着高迁移率封装的石墨烯器件的出现，已经设想并实现了由狄拉克费米光学器件统治的新电子组件。电子光学器件的主要构建模块是栅极定义的p–n结，可引导，传输和折射石墨烯电荷载流子，就像光学中的棱镜和透镜一样。反射和透射受p–n结平滑度的控制，这是常规设备中很难调整的参数。在这里，我们使用扫描门显微镜的极化尖端在石墨烯中创建p–n结，从而在器件电阻中产生Fabry–Pérot干涉条纹。我们使用尖端到石墨烯的距离控制p–n结的平滑度，并使用更平滑的势垒显示出增加的干涉对比度。广泛的紧密结合模拟显示，光滑的势垒会在尖端下方引起狄拉克费米子的明显准约束，从而产生增强的干涉对比。相反，嘘...