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Topological matter

Topological matter

Quasiparticles become massless – but only when they’re moving in the right direction

10 Jan 2025 Isabelle Dumé
Theoretical model of the electronic band structure of ZrSiS, which displays linear dispersion along one axis and quadratic dispersion along another, characteristic of semi-Dirac dispersion
Band structure: Quasiparticles called semi-Dirac fermions were first theorized 16 years ago but were only recently spotted inside a crystal of semi-metal material called ZrSiS. At its crossing points, this material has the electronic band structure shown in the theoretical model above. (Courtesy: Yinming Shao/Penn State)
Physicists at Penn State and Columbia University in the US say they have seen the “smoking gun”

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Isabelle Dumé is a contributing editor to Physics World
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