Negatively charged six-atom manganese clusters similar to the ones above were used to help researchers answer the question, "At what size and how does a cluster of a nominally metallic element become a metal?"

Research offers 1st prediction of size-induced transition to nanoscale half-metallicity
Jennifer deAngelis

The emergence of metallic attributes, usually referred to as the transition to metallicity, is among the most intricate aspects of the size evolution of properties of atomic clusters that are metals in bulk quantities. The question, "At what size and how does a cluster of a nominally metallic element become a metal?" is under active investigation at Argonne and other research centers worldwide. The answer to this question is central for establishing limits of miniaturization in nanoelectronic devices. An even more intricate question is: Can one identify a nanoscale analog of the bulk half-metallic state and the size-driven transition to it? A recent study by Argonne theorists suggests that the answer to this question is yes. Their work represents the first prediction of a nanoscale analog of the bulk half-metallic state.

According to Julius Jellinek (CHM), the lead theorist in the research, even the common metallic state becomes a complex phenomenon at the nanoscale. "Small or medium atomic clusters of metallic elements may not possess at all attributes normally associated with the bulk metallic state," he said. "These attributes then grow in as clusters grow in size. The same should and turns out to be true of the half-metallic state."