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arXiv · 1807.05661

Non-Hermitian Hopf-Link Exceptional Line Semimetals

Zhesen Yang·Jiangping Hu
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Abstract

We study a new class of non-Hermitian topological phases in three dimension in the absence of any symmetry, where the topological robust band degeneracies are Hopf-link exceptional lines. As a concrete example, we investigate the non-Hermitian band structures of nodal line semimetals under non-Hermitian perturbations, where the Fermi surfaces can transit from 1d nodal lines to 2d twisting surfaces with Hopf-link boundaries when the winding number defined along the nodal line is $\pm 1$. The linking numbers of these linked exceptional line phases are also proposed, based on the integral of Chern-Simons form over the Brillouin zone.

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Zhesen Yang, Jiangping Hu. 2019-12-16. Non-Hermitian Hopf-Link Exceptional Line Semimetals. https://doi.org/10.1103/physrevb.99.081102

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