The electro-mechanical properties of a suspended graphene layer are determined by scanning tunneling microscopy (STM) and spectroscopy (STS) measurements and computational simulations of the graphene membrane mechanics and morphology. The graphene membrane is shown to be continuously deformed by controlling the competing interactions with a STM probe tip and the electric field from a back gate electrode. The probe tip induced deformation creates a strain field in the graphene lattice localized on the scale of the probe tip radius. STS measurements on the deformed suspended graphene display an electronic spectrum completely different from graphene supported by a substrate. The spectrum indicates the formation of a spatially confined quantum dot, in agreement with recent predictions of confinement by strain induced pseudomagnetic fields.
Pub Type: Journals
graphene, membranes, scanning tunneling microscopy, scanning tunneling spectroscopy, quantum dots