2015/03/19 by Shin-Ming Huang, Su-Yang Xu, Ilya Belopolski +11 · 2 citations
Physics and Astronomy · #cond-mat.mes-hall
paper · pdf · doi:10.1073/pnas.1514581113
15 pages, 4 Figures
arxiv created 2015/03/19 · arxiv updated 2016/04/27
We identify a Weyl semimetal state in an inversion breaking, stoichiometric compound strontium silicide, SrSi2, with many new and novel properties that are distinct from the TaAs family. We theoretically show that SrSi2 is a Weyl semimetal even without spin-orbit coupling and that, after the inclusion of spin-orbit coupling, two Weyl fermions stick together forming an exotic double Weyl fermion with quadratic dispersions and a higher chiral topological charge of 2. Moreover, we find that the Weyl nodes with opposite charges are located at different energies due to the absence of mirror symmetry in SrSi2, leading to a unique topological quantum response that an external magnetic field can induce a dissipationless current. Our systematic results not only identify a much-needed robust Weyl semimetal candidate but also open the door to new topological Weyl physics that is not possible in the TaAs family of materials.