Electrons in a newly discovered metal, PtSn4, nearly reach speed of light in ways not seen in other materials. Like navigating the seas, electrons are shipped through metals and their movement is governed by the features of their own liquid, the Fermi sea. Like the sea, which can be calm to stormy, with currents and whirlpools that challenge navigation, electrons are shipped through metals governed by the varying topology of the electronic sea, which govern the electron’s speed. To date, only isolated points (Dirac points) with relatively small numbers of conduction electrons have been measured in other materials. PtSn4, with a higher density of conduction electrons, also has extended linear features forming Dirac node arcs. This combination of high electron densities and prominent relativistic properties may lead to a new class of logic devices that use spin instead of charge for information storage and processing and are much faster and energy efficient than those based on silicon.
The image in the center shows a sketch of topological dispersion in PtSn4. The data on the left demonstrate the presence of Dirac cones near edges of the central image. The data on the right show double Dirac dispersion that forms Dirac arc nodes visible near the center of the sketch.
Dirac Node Arcs in PtSn4