A startling new discovery about the movement of atoms at temperatures below zero has been made by an international collaboration of scientists including physicists from Culham Centre for Fusion Energy.

The new research – published in Nature Materials journal – goes against what has previously been scientists’ understanding of the diffusion of atoms in heavy materials.

Scientists believed defects in such materials – like tungsten – would freeze when exposed to cryogenic temperatures, but the new research means the quantum movement of sub-atomic particles is a lot more important than first thought.

This could have applications from superconductors in accelerators to fusion devices.

The research – supported by the theoretical analysis performed by scientists at CCFE, the French National Centre for Scientific Research, and the University of Leeds – now offers evidence that properties of such heavy materials as tungsten can evolve by diffusion of defects even at very low temperatures.

It could have implications for a variety of areas, including research into the best materials to build future nuclear fusion power stations.

Sergei Dudarev

Sergei Dudarev

The discovery – led by Kazuto Arakawa from Shimane University in Japan – is significant because most crystalline materials like tungsten have imperfections in them, known as defects. These defects also form when materials are irradiated by neutrons, causing them to degrade over time.

Sergei Dudarev, Head of the Materials Modelling Group at CCFE, said: “This combined experimental and theoretical study shows that radiation defects in a material as heavy as tungsten can move at low temperatures close to absolute zero. This is a fundamental step in understanding the dynamics of defects.

“The discovery could have a range of materials science and engineering applications – from superconductors in accelerators to fusion devices.”

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