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Arthur T Knackerbracket has found the following story:

A team of researchers from the Universities of Manchester, Nottingham and Loughborough has discovered a quantum phenomenon that helps to understand the fundamental limits of graphene electronics.

Published in Nature Communications, the work describes how electrons in a single atomically-thin sheet of graphene scatter off the vibrating carbon atoms which make up the hexagonal crystal lattice.

By applying a magnetic field perpendicular to the plane of graphene, the current-carrying electrons are forced to move in closed circular "cyclotron" orbits. In pure graphene, the only way in which an electron can escape from this orbit is by bouncing off a "phonon" in a scattering event. These phonons are particle-like bundles of energy and momentum and are the "quanta" of the sound waves associated with the vibrating carbon atom. The phonons are generated in increasing numbers when the graphene crystal is warmed up from very low temperatures.

By passing a small electrical current through the graphene sheet, the team were able to measure precisely the amount of energy and momentum that is transferred between an electron and a phonon during a scattering event.

[...] Mark Greenaway, from Loughborough University, who worked on the quantum theory of this effect, said, "This result is extremely exciting—it opens a new route to probe the properties of phonons in two-dimensional crystals and their heterostructures. This will allow us to better understand electron-phonon interactions in these promising materials, understanding which is vital to develop them for use in new devices and applications."

More information: P. Kumaravadivel et al. Strong magnetophonon oscillations in extra-large graphene, Nature Communications (2019). DOI: 10.1038/s41467-019-11379-3

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