Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 70: Topological Insulators I (joined session with TT)
HL 70.3: Vortrag
Donnerstag, 23. März 2017, 10:15–10:30, POT 251
Occupied topological surface states in strained α-Sn — Victor Rogalev1, •Tomáš Rauch2, Markus Scholz1, Felix Reis1, Lenart Dudy1, Andrzej Fleszar3, Vladimir Strocov4, Jürgen Henk2, Ingrid Mertig2, 5, Jörg Schäfer1, and Ralph Claessen1 — 1Physikalisches Institut und Röntgen Center for Complex Material Systems, Universität Würzburg, 97074 Würzburg, Germany — 2Institute of Physics, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale), Germany — 3Institut für Theoretische Physik und Astronomie, Universität Würzburg, 97074 Würzburg, Germany — 4Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland — 5Max Planck Institute for Microstructure Physics, 06120 Halle (Saale), Germany
Unstrained α-Sn is a semimetal with a non-trivial band ordering at the Γ point of the bulk Brillouin zone: E(Γ8+) > E(Γ7−) > E(Γ7+). Strain in (001) direction lifts the degeneracy of the Γ8+ level at the Fermi energy. We demonstrate that compressive strain turns the system into a strong topological insulator, whereas tensile strain causes a transition into the topological Dirac semimetal phase.
I will present the results of calculations carried out along experimental findings obtained by soft X-ray angle-resolved photoemission. I will show that the existence of a previously unknown surface state located in the occupied projected bulk band structure of α-Sn is unveiled by both experimental and theoretical methods. In addition, its topological origin was confirmed by calculating the topological invariants of the bulk bands.