Topological Semimetals

          @misc{ scivideos_PIRSA:11110137,
            doi = {10.48660/11110137},
            url = {https://pirsa.org/11110137},
            author = {Burkov, Anton},
            keywords = {Quantum Matter},
            language = {en},
            title = {Topological Semimetals},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2011},
            month = {nov},
            note = {PIRSA:11110137 see, \url{https://scivideos.org/pirsa/11110137}}
          }
          

Abstract

I will describe our recent work on a new topological phase of matter: topological Weyl semimetal. This phase arises in three-dimensional (3D) materials, which are close to a critical point between an ordinary and a topological insulator. Breaking time-reversal symmetry in such materials, for example by doping with sufficient amount of magnetic impurities, leads to the formation of a Weyl semimetal phase, with two (or more) 3D Dirac nodes, separated in momentum space. Such a topological Weyl semimetal possesses chiral edge states and a finite Hall conductivity, proportional to the momentum-space separation of the Dirac nodes, in the absence of any external magnetic field. Weyl semimetal demonstrates a qualitatively different type of topological protection: the protection is provided not by the bulk band gap, as in topological insulators, but by the separation of gapless 3D Dirac nodes in momentum space. I will describe a simple way to engineer such materials using superlattice heterostructures, made of thin films of topological insulators. References: arXiv:1110.1089; Phys. Rev. Lett. 107, 127205 (2011); Phys. Rev. B 83, 245428 (2011)."