Working with an international team of scientists, the researchers say their findings provide insights into a 30-year-old theory of how electrons spontaneously quantize and demonstrate a proof-of-principle method to discover new topological magnets. Such quantum magnets hold promise for dissipationless current, high storage capacity, and future green technologies.
Topology is a branch of theoretical mathematics that is already known to play a powerful role in dictating the behavior of electrons in crystals. Topological materials can contain massless particles in the form of light, or photons. In a topological crystal, say the researchers, the electrons often behave like slowed-down light yet, unlike light, carry electrical charge.
Topological phases have been intensely studied in science and engineering and Many new classes of quantum materials with topological electronic structures have been found, including topological insulators and Weyl semimetals. However, say the researchers, while some of the most exciting theoretical ideas require magnetism, most materials explored have been nonmagnetic and show no quantization, leaving many tantalizing possibilities unfulfilled.
"The discovery of a magnetic topological material with quantized behavior," says M. Zahid Hasan, the Eugene Higgins Professor of Physics at Princeton University, who led the research team, "is a major step forward that could unlock new horizons in harnessing quantum topology for future fundamental physics and next-generation device research."
The researchers had been searching for a topological magnetic quantum state that may also operate at room temperature. Recently, they found a materials solution in a kagome lattice - a lattice structure found in many natural minerals' molecular arrangements exhibiting novel physical properties - magnet that is capable of operating at room temperature, which also exhibits the much desired quantization.
"The kagome lattice can be designed to possess relativistic band crossings and strong electron-electron interactions," says Hasan. "Both are essential for novel magnetism. Therefore, we realized that kagome magnets are a promising system in which to search for topological magnet phases as they are like the