A German-Polish research team has succeeded in creating a micrometer-sized space-time crystal consisting of magnons at room temperature. With the help of the scanning transmission X-ray microscope MAXYMUS at Bessy II at Helmholtz Zentrum Berlin, they were able to film the recurring periodic magnetization structure in a crystal. The research project was a collaboration between scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart, Germany, the Adam Mickiewicz University and the Polish Academy of Sciences in Poznań in Poland.
A crystal is a solid whose atoms or molecules are regularly arranged in a particular structure. If one looks at the arrangement with a microscope, one discovers an atom or a molecule always at the same intervals. It is similar with space-time crystals: however, the recurring structure exists not only in space, but also in time. The smallest components are constantly in motion until, after a certain period, they arrange again into the original pattern.
In 2012, the Nobel Prize winner in physics Frank Wilczek discovered the symmetry of matter in time. He is considered the discoverer of these so-called time crystals, although as a theorist he predicted them only hypothetically. Since then, several scientists have searched for materials in which the phenomenon is observed. The fact that space-time crystals actually exist was first confirmed in 2017. However, the structures were only a few nanometers in size and formed only at very cold temperatures below -250 degrees Celsius. The fact that the German-Polish scientists have now succeeded in imaging relatively large space-time crystals of a few micrometers in a video at room temperature is therefore considered groundbreaking. But also because they were able to show that their space-time crystal, which consists of magnons, can interact with other magnons that encounter it.
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Image credit: © MPI-IS