title: Novel Z(2) Topological Metals and Semimetals.
abstract: We report two theoretical discoveries for Z(2) topological metals and semimetals. It is shown first that any dimensional Z(2) Fermi surface is topologically equivalent to a Fermi point. Then the famous conventional no-go theorem, which was merely proven before for Z Fermi points in a periodic system without any discrete symmetry, is generalized so that the total topological charge is zero for all cases. Most remarkably, we find and prove an unconventional strong no-go theorem: all Z(2) Fermi points have the same topological charge ν(Z(2))=1 or 0 for periodic systems. Moreover, we also establish all six topological types of Z(2) models for realistic physical dimensions.
authors.affiliation: Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Y X
authors.initials: YX
authors.lastname: Zhao
authors.affiliation: Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
authors.forename: Z D
authors.initials: ZD
authors.lastname: Wang