Non-Hermitian Hopf-link exceptional line semimetals
Non-Hermitian Hopf-link exceptional line semimetals
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DOI：
10.1103/physrevb.99.081102
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发表时间：
2018-07
影响因子：
3.7
通讯作者：
Zhesen Yang;Jiangping Hu
中科院分区：
文献类型：
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作者：
Zhesen Yang;Jiangping Hu
研究了三维空间中一类新的非厄米拓扑相，其拓扑鲁棒带简并是Hopf-link异常线。作为一个具体的例子，我们研究了在非厄米摄动下的半金属的非厄米带结构，当沿节点线定义的圈数为$\pm 1$时，费米曲面可以从一维节点线过渡到具有Hopf-link边界的二维扭转面。基于chen - simons形式在布里渊区上的积分，提出了这些连接异常线相的连接数。
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.