Researchers at Forschungszentrum Jülich have successfully created the world’s first experimentally verified two-dimensional half metal—a material that conducts electricity using electrons of just one spin type: either “spin-up” or “spin-down.” Their findings, now published as an Editors’ Suggestion in Physical Review Letters, mark a milestone in the quest for materials enabling energy-efficient spintronic that go beyond conventional electronics.

Half metals are key to spintronics: Unlike traditional conductors, half metals allow only one spin orientation to pass through. This makes them ideal candidates for spintronics, a next-generation information technology that leverages both the charge and the spin of electrons for data storage and processing. In conventional electronics, on the other hand, only the charge is used.

However, all known half metals operate only at ultra-low temperatures and lose their special properties at the surface—limiting their use. This was until now, when the team at Forschungszentrum Jülich engineered a 2D half metal in the form of an ultrathin alloy of iron and palladium, just two atoms thick, on a palladium crystal. Using a state-of-the-art imaging technique called spin-resolved momentum microscopy, they showed that the alloy allows only one spin type to conduct, confirming the long-sought 2D half-metallicity.