Mechanically reconfigurable electron confinement in vdW heterostructures via sliding gates

Van der Waals (vdW) heterostructures are very sensitive to their layer structure and orientation, and the low friction between layers allows devices to be reconfigured to modify layer orientation and overlap, which strongly affects their physical properties. We have discovered that microscale gold features deposited on vdW materials can also slide with very low friction. Deposited gold allows for near arbitrary patterning, enabling electrical contact and a strong mechanical grip to move smaller vdW flakes. This greatly expands the scope of possible vdW heterostructure manipulation experiments.

In this talk I will discuss our application of this technique to create a mechanically reconfigurable quantum point contact (QPC) using sliding gold top gate electrodes above an encapsulated graphene heterostructure in the quantum hall regime. We pinch off conduction through the QPC and modify tunnel coupling between edge modes by repositioning the QPC gates.

I will also cover progress in extending our technique to other confinement applications such as mechanically tunable quantum dots as well as towards manipulation of other van der Waals systems, with the goal of achieving novel mechanisms for device modification, scanning probe microscopy, and in situ straining, twisting, and moire sliding.