Resonant tunneling in graphene-boron nitride transistors.

Mark Greenaway (Loughborough)
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Abstract:

Multilayer transistors based on graphene and other van der Waals crystals exhibit many interesting physical properties: high on-off current switching ratios, mechanical flexibility, photoresponsivity, light emission, and resonant tunnelling with gate voltage-tuneable negative differential conductance at room temperature. Here, I will give a brief review of our recent work on electron tunneling between the graphene layers of these devices. I will demonstrate the strong sensitivity of in-plane momentum conserving tunnel transitions to any small misalignment or twist angle between the crystalline lattices of the two graphene electrodes. I will explain how an applied magnetic field can be used to reveal the effects of chirality, which is a unique feature of electron dynamics in graphene and related materials. For devices where there is a large misalignment between the graphene lattices, I will show how phonon emission and defect assisted tunnelling can enable a tunnel current to flow and how these phenomena can be used to probe the properties of the tunnel barrier. Finally, if time permits, I will discuss our recent investigations of the emergence of a magnetically-induced Coulomb gap in the tunnelling current due to electron-electron interactions.