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posted by Fnord666 on Saturday July 27 2019, @11:28AM   Printer-friendly
from the graphic-results dept.

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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  • (Score: 3, Interesting) by Rupert Pupnick on Saturday July 27 2019, @03:43PM (1 child)

    by Rupert Pupnick (7277) on Saturday July 27 2019, @03:43PM (#871974) Journal

    Headline:

    “New quantum phenomenon helps to understand fundamental limits of graphene electronics”

    Seventh paragraph of TFA:

    “The observed phenomenon, commonly referred to as magnetophonon oscillation, was measured in many semiconductors years before the discovery of graphene. It is one of the oldest quantum transport phenomena that has been known for more than 50 years, predating the quantum Hall effect.”

    Are these two phenomena the same? If so, this publication really has a hype problem that it needs to get under control.

    Could I suggest “newly measured” in the headline in place of “new”? Precise wording in tech journalism is important.

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  • (Score: 0) by Anonymous Coward on Saturday July 27 2019, @04:36PM

    by Anonymous Coward on Saturday July 27 2019, @04:36PM (#871999)

    Oof, headlines.

    I feel you man, but the incentives to write poor headlines are way too high to fight. We'll have gotten off coal and oil and Israel and Palestine will have settled their differences long before we get that under control.