A team of international researchers that were led by Scientists at Princeton University have made an exciting discovery. Their discovery tells us that a magnetic material at room temperature enables the particles of electrons to act counterintuitively and to collaborate rather than in singles. Their collective behavior imitates massless particles and anti-particles coexisting unexpectedly and forming an exotic loop-like framework together.
Topology, which a branch of mathematics already known to play an active part in dictating electron conduct in crystals forms the basis for this research and is the key to this conduct. Topological materials in the form of light, or photons, may contain massless particles. The electrons often act like slow-down light in a topological crystal, yet, unlike light, carry an electrical charge.
Topology has acutely seldom been observed in magnetic materials, and the finding of magnetic topological material at room temperature is a step forward. It could unlock new approaches to harnessing topological materials for future technological applications.
Topology in magnetic materials has rarely been found, and finding a magnetic topological material at room temperature is a step advancing that could unlock new solutions to the use of topological components for prospective technological applications.
“Before this job, there was uncertain proof of the topological properties of three-dimensional magnets, which gives us immediate and decisive proof at the microscopic level for this phenomenon,” said Zahid Hasan, who led the work as the Eugene Higgins Professor of Physics at Princeton. “This work opens a fresh continent for topological magnet discovery.”
Zahid Hasan and his team of scientists have dedicated almost a decade studying candidate materials in the search for a topological magnetic quantum state.
Thousands of magnetic materials exist, but many of them did not have the correct properties, the researchers found. The magnets were additionally challenging to synthesize, the magnetism was not sufficiently well recognized, the magnetic structure was complicated to model theoretically, or no conclusive experimental signatures of the topology could be observed.
“After studying many magnetic materials, we performed a measurement on a class of room-temperature magnets and surprisingly saw indications of massless electrons,” answered Ilya Belopolski, a postdoctoral researcher in Hasan’s laboratory and co-first author of the study. “That set us on the path to the discovery of the earliest three-dimensional topological magnetic phase.”
The exotic magnetic crystal consists of cobalt, manganese, and gallium, arranged in an orderly, repeating three-dimensional pattern. To examine the material’s topological state, the researchers used a technique called angle-resolved photoemission spectroscopy. In this experiment, high-intensity light shines on the sample, forcing electrons to release from the surface. These emitted electrons can then be measured, providing information about the way the particles behaved when they were inside the crystal.
An essential aspect of the result is that the material retains its magnetism up to 400 degrees Celsius well above room temperature, satisfying a vital requirement for real-world technological applications.