Ordered states of matter have traditionally been categorized by their broken symmetries, such as the loss of symmetry when spins order in a ferromagnet or liquid freezes into a crystalline solid. Nonetheless, over the past decade a new way of classifying matter has captivated scientists, in which materials can be distinguished by the geometric characteristics, or topology, of their electronic states. These topological materials, which include topological insulators in addition to Dirac and Weyl semimetals, hold great promise for future use in quantum information science and electronics. They possess electronic states that are protected from back scattering, and have potential use as topological switches akin to electronic transistors.
SCIENCE & INNOVATION