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arXiv · 2108.12674

$Z_2$ topology of bismuth

Irene Aguilera·Hyun-Jung Kim·Christoph Friedrich·Gustav Bihlmayer·Stefan Blügel
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Abstract

While first-principles calculations with different levels of sophistication predict a topologically trivial $Z_2$ state for bulk bismuth, some photoemission experiments show surface states consistent with the interpretation of bismuth being in a topologically non-trivial $Z_2$ state. We resolve this contradiction between theory and experiment by showing, based on quasiparticle self-consistent $GW$ calculations, that the experimental surface states interpreted as supporting a non-trivial phase are actually consistent with a trivial $Z_2$ invariant. We identify this contradiction as the result of a crosstalk effect arising from the extreme penetration depth of the surface states into the bulk of Bi. A film of Bi can be considered bulk-like only for thicknesses of about 1000 bilayers ($\approx$ 400 nm) and more.

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Irene Aguilera, Hyun-Jung Kim, Christoph Friedrich, Gustav Bihlmayer, Stefan Blügel. 2021-08-28. $Z_2$ topology of bismuth. https://doi.org/10.1103/physrevmaterials.5.l091201

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