Surface states on a topologically non-trivial semimetal: The case of   Sb(110)
  The electronic structure of Sb(110) is studied by angle-resolved photoemission spectroscopy and first-principle calculations, revealing several electronic surface states in the projected bulk band gaps around the Fermi energy. The dispersion of the states can be interpreted in terms of a strong spin-orbit splitting. The bulk band structure of Sb has the characteristics of a strong topological insulator with a Z2 invariant nu0=1. This puts constraints on the existence of metallic surface states and the expected topology of the surface Fermi contour. However, bulk Sb is a semimetal, not an insulator and these constraints are therefore partly relaxed. This relation of bulk topology and expected surface state dispersion for semimetals is discussed. 
Marco Bianchi, Dandan Guan, Anna Strozecka, Celia H. Voetmann, Shining   Bao, Jose Ignacio Pascual, Asier Eiguren, Philip Ho...
cond-mat.str-el cond-mat.mes-hall cond-mat.mtrl-sci