Graphene levitons and anti-levitons in magnetic fields

What is it about?

Graphene is a single layer of graphite. A unique surfing electron state can emerge atop the sea of electrons that has the potential to produce a new form of electronics with characteristics analogous to many phenomena found in specialised optics, e.g. negative refraction. A magnetic field can control the trajectories of the particles.

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Why is it important?

In this work we describe “levitons” in a graphene system and their amazing properties. We fully describe the soliton-like behaviour of the leviton as it encounters a potential step. Inside the potential step an anti-leviton forms. The leviton transmission and propagation through the graphene, in magnetic fields ranging from the very small, B=5milliTesla, to the moderately large, B=6.5 Tesla where Landau quantisation occurs results in many new discoveries. We demonstrate that we can control the transmission of the leviton into a potential step and switch Klein tunnelling on and off with magnetic field pulses. We give a complete description of the leviton energy with respect to the height of the step and the phenomena that occur as a function of this ratio. We create phase diagrams and elucidate the fempto-second responses of the systems. We discover a new quasiparticle excitation that we call the levity vortex. This work gives unprecedented clarity to the propagation of a very special electronic wavefunction as it rides the Fermi sea.