Nav: Home

How to melt gold at room temperature

November 20, 2018

When the tension rises, unexpected things can happen - not least when it comes to gold atoms. Researchers from, among others, Chalmers University of Technology, Sweden, have now managed, for the first time, 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 was interested to see how it influenced the gold atoms.

It was when he studied the atoms in the recordings from the microscope, that he saw something exciting. The surface layers of gold had actually melted - at room temperature.

"I was really stunned by the discovery. This is an extraordinary phenomenon, and it gives us new, foundational knowledge of gold," says Ludvig de Knoop.

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. Upon further experimentation, the researchers discovered that it was 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 just spectacular, but also groundbreaking scientifically. Together with the theoretician Mikael Juhani Kuisma, from the University of Jyväskylä in Finland, Ludvig de Knoop and colleagues have opened up new avenues in materials science. The results are now published in the journal Physical Review Materials.

Thanks to theoretical calculations, the researchers are able to suggest why gold can melt at room temperature. Possibly, the surface melting can be seen as a so-called low-dimensional phase transition. In that case, the discovery is connected to the research field of topology, where pioneers David Thouless, Duncan Haldane and Michael Kosterlitz received the Nobel Prize in Physics 2016. With Mikael Juhani Kuisma in the lead, the researchers are now looking into that possibility.

In any case, the ability to melt surface layers of gold in this manner enables 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 could be used in different types of sensors, catalysts and transistors. There could also be opportunities for new concepts for contactless components," says Eva Olsson, Professor at the Department of Physics at Chalmers.

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

The article "Electric-field-controlled reversible order-disorder switching of a metal tip surface" has been published in the journal Physical Review Materials. It was written by Ludvig de Knoop, Mikael Juhani Kuisma, Joakim Löfgren, Kristof Lodewijks, Mattias Thuvander, Paul Erhart, Alexandre Dmitriev and Eva Olsson. The researchers behind the results are active at Chalmers, Gothenburg University, the University of Jyväskylä in Finland, and Stanford University in the United States.

More about the research infrastructure at Chalmers

The Chalmers Material Analysis Laboratory (CMAL) has advanced instruments for material research. The laboratory formally belongs to the Department of Physics, but is open to all researchers from universities, institutes and industry. The experiments in this study have been carried out using advanced and high-resolution electron microscopes - in this case, transmission electron microscopes (TEM). Major investments have recently been made, to further push the laboratory to the forefront of material research. In total, the investments are about 66 million Swedish kronor, of which the Knut and Alice Wallenberg Foundation has contributed half.

Read more about Chalmers Material Analysis Laboratory here.

More about electron microscopy

Electron microscopy is a collective name for different types of microscopy, using electrons instead of electromagnetic radiation to produce images of very small objects. Using this technique makes it possible to study individual atoms. There are different types of electron microscopes, such as transmission electron microscopes (TEM), scanning transmission electron microscopes (STEM), scanning electron microscopes (SEM) and combined Focused Ion Beam and SEM (FIB-SEM).

For more information, contact:

Ludvig de Knoop
Post-doctoral researcher in Physics
Chalmers
ludvig.deknoop@chalmers.se
+46 31 772 51 80

Eva Olsson
Professor of Physics, Chalmers
eva.olsson@chalmers.se
+46 31 772 32 47

Chalmers University of Technology

Related Microscope Articles:

Microscope can scan tumors during surgery and examine cancer biopsies in 3-D
A new UW microscope could provide accurate real-time results during cancer-removal surgeries, potentially eliminating the 20 to 40 percent of women who have to undergo multiple lumpectomy surgeries because cancerous breast tissue is missed the first time around.
Next-gen steel under the microscope
Next-generation steel and metal alloys are a step closer to reality, thanks to an international research project involving a University of Queensland scientist.
Engineers shrink microscope to dime-sized device
Researchers at The University of Texas at Dallas have created an atomic force microscope on a chip, dramatically shrinking the size -- and, hopefully, the price tag -- of a high-tech device commonly used to characterize material properties.
Protein research: The computer as microscope
Using a combination of infrared spectroscopy and computer simulation, researchers at Ruhr-Universität Bochum have gained new insights into the workings of protein switches.
New microscope chemically identifies micron-sized particles
A team from MIT Lincoln Labs have developed a microscope that can chemically identify individual micron-sized particles.
The self-driving microscope
Researchers develop a combination of software and hardware for adaptive live imaging of large living organisms.
Smart microscope adapts to changes in live specimens
HHMI/Janelia Research Campus scientists have developed the first adaptive light-sheet microscope -- a smart microscope that continuously analyzes and adapts to dynamic changes in a specimen and thereby improves spatial resolution.
Nanowires as sensors in new type of atomic force microscope
A new type of atomic force microscope (AFM) uses nanowires as tiny sensors.
Smartphone microscope creates interactive tool for microbiology
An easily assembled smartphone microscope provides new ways of interacting with and learning about common microbes.
Microscope imaging system integrates virtual reality technology
CaptiView is a microscope image injection system that overlays critical virtual reality imaging directly onto the brain when viewed through the eyepiece during surgery.

Related Microscope Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Changing The World
What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.
Now Playing: Science for the People

#521 The Curious Life of Krill
Krill may be one of the most abundant forms of life on our planet... but it turns out we don't know that much about them. For a create that underpins a massive ocean ecosystem and lives in our oceans in massive numbers, they're surprisingly difficult to study. We sit down and shine some light on these underappreciated crustaceans with Stephen Nicol, Adjunct Professor at the University of Tasmania, Scientific Advisor to the Association of Responsible Krill Harvesting Companies, and author of the book "The Curious Life of Krill: A Conservation Story from the Bottom of the World".