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arXiv · 2008.01090

Exceptional Topological Insulators

M. Michael Denner·Anastasiia Skurativska·Frank Schindler·Mark H. Fischer·Ronny Thomale·Tomáš Bzdušek·Titus Neupert
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Abstract

We introduce the exceptional topological insulator (ETI), a non-Hermitian topological state of matter that features exotic non-Hermitian surface states which can only exist within the three-dimensional topological bulk embedding. We show how this phase can evolve from a Weyl semimetal or Hermitian three-dimensional topological insulator close to criticality when quasiparticles acquire a finite lifetime. The ETI does not require any symmetry to be stabilized. It is characterized by a bulk energy point gap, and exhibits robust surface states that cover the bulk gap as a single sheet of complex eigenvalues or with a single exceptional point. The ETI can be induced universally in gapless solid-state systems, thereby setting a paradigm for non-Hermitian topological matter.

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M. Michael Denner, Anastasiia Skurativska, Frank Schindler, Mark H. Fischer, Ronny Thomale, Tomáš Bzdušek, Titus Neupert. 2020-08-03. Exceptional Topological Insulators. https://doi.org/10.1038/s41467-021-25947-z

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