Surface exceptional points in a topological Kondo insulator
Surface exceptional points in a topological Kondo insulator
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DOI：
10.1103/physrevb.104.235153
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发表时间：
2021-09
影响因子：
3.7
通讯作者：
R. Peters;K. Kimura;Y. Michishita;Tsuneya Yoshida;N. Kawakami
中科院分区：
文献类型：
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作者：
R. Peters;K. Kimura;Y. Michishita;Tsuneya Yoshida;N. Kawakami
相关的材料已经出现作为一个竞技场，以研究非厄米效应，典型的例子是出现的例外点。我们在这里表明，拓扑近藤绝缘体是一个理想的平台，研究这些现象，由于强相关性和表面状态表现出一个非平凡的自旋纹理。使用数值模拟，我们证明了出现例外点的单粒子绿色的功能上的材料的表面上，而大部分仍然是绝缘的。我们揭示了具有长寿命的准粒子态是如何在表面上通过非厄米效应产生的，而狄拉克锥被涂抹，这解释了表面近藤击穿，在该击穿处，重狄拉克锥从单粒子光谱中消失，并被轻态所取代。我们进一步展示了非Hermiticty如何改变表面状态中固有的自旋纹理，这可能有助于通过实验确定例外点。除了证实拓扑近藤绝缘体表面存在非厄米效应外，本文还论证了描述单粒子绿色函数的有效非厄米矩阵的本征态和本征值如何有助于理解相关材料的性质。
Correlated materials have appeared as an arena to study non-Hermitian effects as typically exemplified by the emergence of exceptional points. We show here that topological Kondo insulators are an ideal platform for studying these phenomena due to strong correlations and surface states exhibiting a nontrivial spin texture. Using numerical simulations, we demonstrate the emergence of exceptional points in the single-particle Green’s function on the surface of the material while the bulk is still insulating. We reveal how quasiparticle states with long lifetimes are created on the surface by non-Hermitian effects while the Dirac cones are smeared, which explains the surface Kondo breakdown at which heavy Dirac cones disappear from the single-particle spectrum and are replaced by light states. We further show how the non-Hermiticty changes the spin texture inherent in the surface states, which might help identify exceptional points experimentally. Besides confirming the existence of non-Hermitian effects on the surface of a topological Kondo insulator, this paper demonstrates how the eigenstates and eigenvalues of the effective non-Hermitian matrix describing the single-particle Green’s function help understand the properties of correlated materials.