Classification of Exceptional Points and Non-Hermitian Topological Semimetals
Classification of Exceptional Points and Non-Hermitian Topological Semimetals
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DOI：
10.1103/physrevlett.123.066405
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发表时间：
2019-08-09
影响因子：
8.6
通讯作者：
Sato, Masatoshi
中科院分区：
文献类型：
--
作者：
Kawabata, Kohei;Bessho, Takumi;Sato, Masatoshi
例外点是由非厄米性引起的普适能级简并。虽然过去几十年见证了他们的新物理学，但尚未获得统一的理解。在这里，我们提出了完整的分类通用拓扑稳定的例外点，根据两种类型的复杂的能隙和基本对称性的电荷共轭，宇称，和时间反转。这种分类揭示了独特的非厄米无隙结构，没有厄米类似物，并系统地预测未知的非厄米半金属和节点超导体;一个拓扑哑铃的特殊点在三维构造作为一个例子。我们的工作铺平了道路，走向更丰富的特殊点和非厄米拓扑半金属的现象和功能。
Exceptional points are universal level degeneracies induced by non-Hermiticity. Whereas past decades witnessed their new physics, the unified understanding has yet to be obtained. Here we present the complete classification of generic topologically stable exceptional points according to two types of complex-energy gaps and fundamental symmetries of charge conjugation, parity, and time reversal. This classification reveals unique non-Hermitian gapless structures with no Hermitian analogs and systematically predicts unknown non-Hermitian semimetals and nodal superconductors; a topological dumbbell of exceptional points in three dimensions is constructed as an illustration. Our work paves the way toward richer phenomena and functionalities of exceptional points and non-Hermitian topological semimetals.