To take a picture, the best digital cameras on the market open the shutter for about 1/4000th of a second.
We need a faster clicking shutter to take snapshots of atomic activity.
With this in mind, scientists have shown how to achieve shutter speeds of just one trillionth of a second, or 250 million times faster than digital cameras. This makes it possible to capture something very important in materials science: dynamic disorder.
Simply put, a cluster of atoms moves or dances in a material in a certain way over a certain period of time, caused by things like vibrations or temperature changes. This is not yet a fully understood phenomenon, but it is of great importance to the properties and reactions of materials.
A new ultra-fast shutter speed system announced in March this year gives us even more insight into what’s going on in dynamic chaos. The researchers call their invention Variable Shutter Atom Pair Distribution Function, or vsPDF for short.
“The only time you can really see this side of the material is with this new vsPDF tool.” Said Materials scientist Simon Billinge of Columbia University in New York.
“With this technology, we can look at the material and see which atoms are dancing and which are not.”
A fast shutter speed captures more accurate time snapshots, which is useful for fast-moving objects such as rapidly swaying atoms. For example, a slow shutter speed in a photo of a sports game will blur out the players in the frame.
For blazingly fast snaps, vsPDF uses neutrons to measure the position of atoms rather than traditional photographic techniques. The way neutrons hit and pass through matter can be tracked to measure surrounding atoms, and changes in energy levels are equivalent to adjusting shutter speed.
These shutter speed variations are as important as the trillionth of a second shutter speed. These are essential for distinguishing a dynamic disturbance from another static disturbance of relative interest (the normal background swaying with atomic spots). It does not enhance the functionality of the material.
“This provides us with a whole new way of unraveling the complexity of what is happening inside complex materials and the hidden effects that can maximize their properties.” Said Billinge.
In this case, the researchers trained the neutron camera with the following substances: germanium telluride (GeTe) is widely used to convert waste heat into electricity and electricity into cooling due to its special properties.
The camera revealed that the GeTe remained structured as crystals. on average, at any temperature. At higher temperatures, however, they exhibited a more dynamic disorder in which the atoms converted their motion into thermal energy following a gradient consistent with the direction of the material’s spontaneous polarization.
A deeper understanding of these physical structures will improve our knowledge of how thermoelectric elements work, allowing us to make better use of them, such as the equipment that powers Mars rovers when sunlight is not available. You will be able to develop materials and equipment.
We can improve our scientific understanding of these materials and processes through models based on new camera observations. However, there is still a lot of work to be done before vsPDF can be widely used as a testing method.
“We expect the vsPDF technique described here to become a standard tool for reconciling the local and average structures of energetic materials,” the researchers said. explained in their paper.
This research Natural materials.
A previous version of this article was published in March 2023.