Department of Physics and Astronomy, Rutgers University , Piscataway, New Jersey 08854, United States.
Advanced Materials Laboratory, National Institute for Materials Science , 1-1 Namiki, Tsukuba 305-0044, Japan.
Nano Lett. 2017 May 10;17(5):2839-2843. doi: 10.1021/acs.nanolett.6b05228. Epub 2017 Apr 24.
Graphene's remarkable properties are inherent to its two-dimensional honeycomb lattice structure. Its low dimensionality, which makes it possible to rearrange the atoms by applying an external force, offers the intriguing prospect of mechanically controlling the electronic properties. In the presence of strain, graphene develops a pseudomagnetic field (PMF) that reconstructs the band structure into pseudo Landau levels (PLLs). However, a feasible route to realizing, characterizing and controlling PMFs is still lacking. Here we report on a method to generate and characterize PMFs in a graphene membrane supported on nanopillars. A direct measure of the local strain is achieved by using the magnifying effect of the moiré pattern formed against a hexagonal boron nitride substrate under scanning tunneling microscopy. We quantify the strain-induced PMF through the PLLs spectra observed in scanning tunneling spectroscopy. This work provides a pathway to strain induced engineering and electro-mechanical graphene-based devices.
石墨烯的卓越性质源于其二维蜂窝状晶格结构。其低维性使得通过施加外力可以重新排列原子，从而提供了机械控制电子性质的诱人前景。在应变存在的情况下，石墨烯会产生赝磁场（PMF），从而将能带结构重构为赝朗道能级（PLLs）。然而，实现、表征和控制 PMF 的可行途径仍然缺乏。在这里，我们报告了一种在纳米柱支撑的石墨烯膜中产生和表征 PMF 的方法。通过使用扫描隧道显微镜下与六方氮化硼衬底形成的莫尔图案的放大效应，直接测量局部应变。我们通过在扫描隧道光谱中观察到的 PLL 光谱来量化应变诱导的 PMF。这项工作为应变诱导的工程和机电石墨烯基器件提供了一条途径。
