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arXiv · 2102.05667

Geometric Response and Disclination-Induced Skin Effects in Non-Hermitian Systems

Xiao-Qi Sun·Penghao Zhu·Taylor L. Hughes
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Abstract

We study the geometric response of three-dimensional non-Hermitian crystalline systems with nontrivial point-gap topology. For systems with fourfold rotation symmetry, we show that in the presence of disclination lines with a total Frank angle which is an integer multiple of $2\pi$, there can be nontrivial one-dimensional point-gap topology along the direction of the disclination lines. This results in disclination-induced non-Hermitian skin effects. By doubling a non-Hermitian Hamiltonian to a Hermitian three-dimensional chiral topological insulator, we show that the disclination-induced skin modes are zero modes of the effective surface Dirac fermion(s) in the presence of a pseudomagnetic flux induced by disclinations. Furthermore, we find that our results have a field theoretic description, and the corresponding geometric response actions (e.g., the Euclidean Wen-Zee action) enrich the topological field theory of non-Hermitian systems.

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Xiao-Qi Sun, Penghao Zhu, Taylor L. Hughes. 2021-02-10. Geometric Response and Disclination-Induced Skin Effects in Non-Hermitian Systems. https://doi.org/10.1103/physrevlett.127.066401

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