Mikkel Settnes, Stephen Power, Dirch H. Petersen & Antti-Pekka Jauho, DTU Nanotech, Technical University of Denmark, Kgs. Lyngby 2800, Denmark. 

Contacting graphene using movable probes shows great potential as characterization method of individual nanostructures. It reduces the contamination related to fabrication of fixed contacts while allowing for flexible investigation of single nanostructures and their effect on transport properties.

Conventional transport calculations use a Landauer geometry containing two (or more) semi-infinite contacts, and a finite sample. Here, on the other hand, we consider an infinite sample, which is probed locally by several probes. We present a combination of recursive Green’s function methods and carefully constructed boundary self-energies to treat such infinite systems containing spatially localized features.

The method is not limited to calculations on point probes. It also allows us to calculate the properties of isolated nanostructures without relying on periodic boundary conditions that leads to a repetition of both probes and structures.

We use this to calculate the transport properties of a single strained nanobubble in an otherwise pristine graphene sheet. We calculate the electronic properties of the bubble and demonstrate how the pseudomagnetic field caused by the strain, shapes the current paths as the electrons traverse the strain field. 

Mikkel Settnes obtained his master’s degree in Physics and Nanotechnology in 2012 at the Technical University of Denmark (DTU) in the Department of Photonics focusing on light matter interaction in solid state optical cavity systems. He is currently a PhD student at DTU Nanotech under the supervision of Professor Antti-Pekka Jauho. His project is consists of theoretical calculations of electron transport in graphene with a focus on multiple probes and disordered systems.