Ames boffins mix metals to boost electron velocity

c those charges move

A platinum-tin “topological metal” discovered by the Department of Energy's Ames Laboratory could cut energy needed in computing applications, by moving electrons around faster.

A topological quantum material – a class of stuff that includes superconductors – has a characteristic that's handy for electronics: electrons travel faster in such materials than they do through, for example, copper.

While electromagnetic waves can travel through copper at between 66 and 99 per cent of c (the speed of light in a vacuum), depending on the characteristics of the cable, the electrons themselves are sluggish indeed: fractions of metres per second.

Anywhere you need the electrons, not just the waves, to move faster, the easiest way is to apply more voltage, so a material like the PtSn4 that lets electrons move around quickly reduces the energy in a system.

From the Ames release: “The electrons in topological quantum materials can travel close to speed of light thanks to unique property called Dirac dispersion.”

Most such materials have only a few Dirac points and therefore low numbers of what the release calls “conduction electrons” available.

“In PtSn4, the scientists not only discovered a high density of conduction electrons, but also large number of closely positioned Dirac points forming extended lines or Dirac node arcs”, the release continues.

The researchers used a laser-based “angle-resolved photoemission spectroscopy instrument” to visualise the behaviour of the PtSn4 in high resolution.

Their work is published in this paper (abstract) in Nature Physics.


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