title: Topological states on the gold surface.
abstract: Gold surfaces host special electronic states that have been understood as a prototype of Shockley surface states. These surface states are commonly employed to benchmark the capability of angle-resolved photoemission spectroscopy (ARPES) and scanning tunnelling spectroscopy. Here we show that these Shockley surface states can be reinterpreted as topologically derived surface states (TDSSs) of a topological insulator (TI), a recently discovered quantum state. Based on band structure calculations, the Z2-type invariants of gold can be well-defined to characterize a TI. Further, our ARPES measurement validates TDSSs by detecting the dispersion of unoccupied surface states. The same TDSSs are also recognized on surfaces of other well-known noble metals (for example, silver, copper, platinum and palladium), which shines a new light on these long-known surface states.
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.|Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany.|School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China.
authors.forename: Binghai
authors.identifier: http://orcid.org/0000-0003-2164-5839
authors.initials: B
authors.lastname: Yan
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stadtmüller
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Norman
authors.identifier: http://orcid.org/0000-0002-2124-1482
authors.initials: N
authors.lastname: Haag
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Jakobs
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Seidel
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Jungkenn
authors.affiliation: I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Mathias
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Mirko
authors.initials: M
authors.lastname: Cinchetti
authors.affiliation: Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67653 Kaiserslautern, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Aeschlimann
authors.affiliation: Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Felser