Abstract
Topological insulators are solid state systems of independent electrons for which the Fermi level lies in a mobility gap, but the Fermi projection is nevertheless topologically non-trivial, namely it cannot be deformed into that of a normal insulator. This non-trivial topology is encoded in adequately defined invariants and implies the existence of surface states that are not susceptible to Anderson localization. This non-technical review reports on recent progress in the understanding of the underlying mathematical structures, with a particular focus on index theory.
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Acknowledgements
The author thanks his main collaborators Jean Bellissard, Johannes Kellendonk and Emil Prodan as well as further coauthors Giuseppe De Nittis, Stefan Teufel, Julian Grossmann, Carlos Villegas, Julio Cesar Avila, Alan Carey and John Phillips for inspiring intellectual input and persistence. This work is in part supported by the DFG.
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Schulz-Baldes, H. Topological Insulators from the Perspective of Non-commutative Geometry and Index Theory. Jahresber. Dtsch. Math. Ver. 118, 247–273 (2016). https://doi.org/10.1365/s13291-016-0142-5
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DOI: https://doi.org/10.1365/s13291-016-0142-5