Magnetic imaging of electronic transport in graphene*

We study electronic transport in graphene devices using scanning superconducting quantum interference device (SQUID) microscopy. Specifically, we image the magnetic fields originating from current flow inside a device. This allows us to visualize current patterns from different transport regimes in graphene by reconstructing the current density from the magnetic field images. A secondary measurement involves studying the response of a device to a small, localized magnetic field applied using an integrated current loop on the SQUID. This allows us to assess the performance of these devices as scanning Hall probes, which will enable magnetic imaging up to room temperature and at high magnetic fields. We report on our progress towards these measurements and present simulations of electronic transport in different regimes. The simulations inform our choice of device geometry and help us evaluate the feasibility of these measurements.