IRG-1 Researchers Professor Nandini Trivedi and her graduate student Tim McCormick, in collaboration with Professor Adam Kaminski (Iowa State University) and Dr. Jiaqiang Yan (ORNL) and their students, discovered a new electronic phase of matter known as a topological Weyl semimetal. This novel quantum phase hosts excitations known as Weyl fermions, first predicted in high energy physics in 1929 but only recently experimentally discovered in quantum materials. Using theoretical modeling and angle-resolved photoemission spectroscopy, the team identified the first type-II Weyl semimetal phase in the layered transition metal compound MoTe2. Type-II Weyl fermions break Lorentz invariance, a symmetry obeyed by all fundamental particles, so Weyl semimetals hosting these excitations allow for the testing of exotic physics beyond the standard model in a tabletop experiment. They possess electron and hole pockets that touch at topologically protected points in momentum space and form Fermi arcs and newly predicted track states on the surface that result in unique magneto-transport properties of these materials. Additionally, the Weyl excitations are robust against external perturbations, providing a resilient platform for possible information storage as well as opening the door for electronic applications. Read the new publication in Nature Materials.
