Weyl semi-metals : a short review

Abstract: We begin this review with an introduction and a discussion of Weyl fermions as emergent particles in condensed matter systems, and explain how high energy phenomena like the chiral anomaly can be seen in low energy experiments. We then explain the current interest in the field due to the recent discovery of real materials which behave like Weyl semi-metals. We then describe a simple lattice model of a topological insulator, which can be turned into a Weyl semi-metal on breaking either time-reversal or inversion symmetry, and show how flat bands or Fermi arcs develop. Finally, we describe some new phenomena which occur due to the chiral nature of the Weyl nodes and end with possible future prospects in the field, both in theory and experiment.