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arXiv · 1701.03421

Double Band Inversion in $ \alpha $-Sn: Appearance of Topological Surface States and the Role of Orbital Composition

Victor A. Rogalev·Tomáš Rauch·Markus R. Scholz·Felix Reis·Lenart Dudy·Andrzej Fleszar·Marius-Adrian Husanu·Vladimir N. Strocov·Jürgen Henk·Ingrid Mertig·Jörg Schäfer·Ralph Claessen
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Abstract

The electronic structure of \graySn(001) thin films strained compressively in-plane was studied both experimentally and theoretically. A new topological surface state (TSS) located entirely within the gapless projected bulk bands is revealed by \textit{ab initio}-based tight-binding calculations as well as directly accessed by soft X-ray angle-resolved photoemission. The topological character of this state, which is a surface resonance, is confirmed by unravelling the band inversion and by calculating the topological invariants. In agreement with experiment, electronic structure calculations show the maximum density of states in the subsurface region, while the already established TSS near the Fermi level is strongly localized at the surface. Such varied behavior is explained by the differences in orbital composition between the specific TSS and its associated bulk states, respectively. This provides an orbital protection mechanism for topological states against mixing with the background of bulk bands.

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Victor A. Rogalev, Tomáš Rauch, Markus R. Scholz, Felix Reis, Lenart Dudy, Andrzej Fleszar, Marius-Adrian Husanu, Vladimir N. Strocov, Jürgen Henk, Ingrid Mertig, Jörg Schäfer, Ralph Claessen. 2017-01-12. Double Band Inversion in $ \alpha $-Sn: Appearance of Topological Surface States and the Role of Orbital Composition. https://doi.org/10.1103/physrevb.95.161117

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