Ever since the discovery of the quantum Hall effect (Nobel Prize 1985), symmetry has been the guiding principle in the search for topological materials. Now an international team of researchers from Germany, Switzerland, and the U.S. has introduced an alternative guiding principle, "quasi-symmetry," which leads to the discovery of a new type of topological material with great potential for applications in spintronics and quantum technologies. This work has been published in Nature Physics.
