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O: Fachverband Oberflächenphysik
O 100: Electronic Structure of Surfaces: Spectroscopy, Surface States II
O 100.1: Talk
Thursday, March 23, 2017, 16:00–16:15, WIL C307
Existence of Topological Nontrivial Surface States in Strained Transition Metals: W, Ta, Mo, and Nb — Danny Thonig1, Tomáš Rauch2, Hossein Mirhosseini3, •Jürgen Henk2, Ingrid Mertig2,3, Henry Wortelen4, Bernd Engelkamp4, Anke B. Schmidt4, and Markus Donath4 — 1University Uppsala, Sweden — 2Martin Luther University Halle-Wittenberg — 3Max Planck Institute of Microstructure Physics, Halle — 4Westfälische Wilhelms-Universität, Münster
We show that a series of transition metals with strained body-centered cubic lattice—W, Ta, Nb, and Mo—hosts surface states that are topologically protected by mirror symmetry and, thus, exhibits nonzero topological invariants. These findings, reported in [1], extend the class of topologically nontrivial systems by topological crystalline transition metals. The investigation is based on calculations of the electronic structures and of topological invariants. The signatures of a Dirac-type surface state in W(110), e. g., the linear dispersion and the spin texture, are verified. To further support our prediction, we investigate Ta(110) both theoretically and experimentally by spin-resolved inverse photoemission: unoccupied topologically nontrivial surface states are observed.
[1] D. Thonig et al., Phys. Rev. B 94 (2016) 155132.