Local strain induced nanoscale double-wrinkles in graphene realized by STM tip-directed sliding

Creating nano-scale wrinkles in graphene by strain engineering is an effective strategy to introduce exotic electronic and optoelectronic properties into the material. However, it's challenging to realize atomic precision local strain at specific locations on the surface. Herein, we report on a local strain engineering approach to building nano-wrinkles by scanning tunneling microscope (STM) tip-directed sliding of the monolayer graphene on highly ordered pyrolytic graphite (HOPG). Unique parallel double wrinkles are formed due to the sliding caused displacement being locked by the instantly formed bonds at the edge. They can also be removed by applying a voltage pulse to release the edge locking. Scanning tunning spectra reveals typical 1D quantum characteristics of van Hove singularity peaks on the wrinkles, while fast Fourier transform (FFT) analysis of high-resolution image reveals intralayer lattice distortion and interlayer twisting caused by anisotropic residual tensile and compressive stresses in the vicinity of the wrinkles. Additionally, structural kinks on the wrinkles have been created by controlled tip contact, which induces local Kekulé bond order near the kink due to the tensile stress breaking the bond symmetry of graphene. Our work provides a new technique to realize desired physical properties via local strain engineering of layered 2D materials.