Tunable Short Periodic Superlattices in Graphene

这个项目的目的是对一维周期势调制的石墨烯中预测的超晶格效应进行实验演示。虽然二维超晶格已经被许多小组进行了实验研究，例如证明了Hofstadter物理，但一维超晶格也应该导致石墨烯能带结构的强烈修改，这在实验中还没有表现出来。利用嵌入在氮化硼中的高迁移率石墨烯和由薄的几层石墨烯制成的图案化栅极，我们将在传输层施加一个短周期、可调的调制势，并通过磁聚焦实验研究由此产生的各向异性能带结构，以及Shubnikov-de Haas振荡的热阻。此外，我们还将研究强一维调制的石墨烯中可能存在的Bloch振荡、umclapp电子-电子散射和额外的朗道能级。

This project aims at an experimental demonstration of predicted superlattice effects in graphene modulated by a one-dimensional periodic potential. While two-dimensional superlattices have been studied experimentally by a number of groups, demonstrating, e.g., Hofstadter physics, one-dimensional superlattices should also lead to a strong modification of the graphene band structure, which has not yet been shown in experiment. Using high-mobility graphene embedded in boron nitride and patterned gates fabricated out of thin few-layer graphene, we will apply a short-period, tunable modulation potential to the transport layer, and study the resulting anisotropic band structure by magnetic focusing experiments, and the thermal damping of Shubnikov-de Haas oscillations. In addition, we will search for Bloch oscillations, umklapp electron-electron scattering and additional Landau levels predicted to exist in graphene with a strong 1D modulation.