How to dissolve gold at room temperature

Alexander Erikson

The painting shows the atoms of a gold cone exposed to a powerful electric field. We also see the field (around the top of the cone) that excites the gold atoms. They break almost all their connections to each other and the surface strata begin to melt.

When the tension rises, unexpected things may happen – not least when it comes to gold atoms. The researchers of, among others, Chalmers University of Technology, Sweden, have now managed to make the surface of a gold object melt at room temperature.

Ludvig de Knoop, from Chalmers' Department of Physics, placed a small piece of gold in an electron microscope. Observing it at the highest level of magnification and increasing the electric field step-by-step to extremely high levels, he is interested to see how it influences the gold atoms.

It was when he studied the atoms in the recordings of the microscope, that he saw something exciting. The surface liners of gold have actually dissolved – at room temperature.

"I was really stunned by the discovery, this is an extraordinary phenomenon, and it gives us a new, foundational knowledge of gold," says Ludwig the junction.

What happened was that the gold atoms became excited. Under the influence of the electric field, they suddenly lost their ordered structure and released almost all their connections to each other. On further experiments, the researchers found that it is also possible to switch between a solid and a molten structure.

The discovery of how gold atoms can lose their structure in this way is not only spectacular, but also breaks brains. Together with the theoretical Michael Jahan Kuisma, from the University of Jivskilän in Finland Ludvig de Knoop and colleagues opened new avenues in materials science.

Thanks to the theoretical calculations, the researchers are able to suggest what gold can melt at room temperature. Maybe, the surface melting can be seen as a so-called low-dimensional phase transition. In this case, discovery is associated with the topology research, where the pioneer David Thols, Duncan Haldane and Michael Costerlitz received the Nobel Prize in Physics in 2016. With Michael Juhani Kuyska in the lead, the researchers are now looking at that possibility.

In any case, the ability to melt surface layers of gold in this manner ensures various novel practical applications in the future.

"Because we can control and change the properties of the surface atom layers, it opens doors for different kinds of applications, for example, the technology can be used in different types of sensors, catalysts and transistors. There may also be new opportunities for new concepts For Contactless Components, "says Eva Olson, Professor at the Department of Physics in Chambers.

But for now, for those who want to melt gold without an electron microscope, a trip to the goldsmith is still in order.

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