This image shows a snowflake a few nanometers in size, which is not made of ice but of crystallized zinc atoms.
In order to develop new techniques and technologies with nanomaterials, researchers from Australia and New Zealand have experimented with gallium, among other things. This should help to understand the interaction of different atoms. Gallium is a rare, soft metal that liquefies at room temperature. Other metals such as zinc, copper, nickel or aluminum dissolve very easily in the liquid gallium at high temperatures. When the mixture is lowered back to room temperature, they crystallize while the gallium remains liquid.
The resulting metal crystals appeared in a variety of shapes: cubes, rods, hexagonal plates and the snowflake structure shown in the picture. The scientists were able to show that the symmetry of the shapes remains constant, depending on the dissolved metal. Surprisingly, experiments with zinc have always resulted in the snowflake pattern - a six-branched symmetry in which each atom is surrounded by six equally spaced neighbors.
With these results, the scientists were able to show that liquid gallium does not have a random structure, as assumed, but rather forms specifically formed crystals in interaction with different metals. These findings open up new avenues for research with nanostructures. These are used, for example, in the manufacture of electronics by specifically generating specific properties in the nano range.
'In contrast to top-down approaches to forming nanostructures - by cutting away material - this bottom-up approach relies on the self-assembly of atoms,' says Nicola Gaston of the MacDiarmid Institute for Advanced Materials and Nanotechnology at the University of Auckland. "This is how nature makes nanoparticles, and it's both less wasteful and much more precise than a top-down method." She also thinks, "There's also something very cool about creating a metallic snowflake!"