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arXiv · 2011.09797

Plasmons in Two-Dimensional Topological Insulators

Henning Schlömer·Zhihao Jiang·Stephan Haas
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Abstract

We analyze collective excitations in models of two-dimensional topological insulators using the random phase approximation. In a two-dimensional extension of the Su-Schrieffer-Heeger model, edge plasmonic excitations with induced charge-density distributions localized at the boundaries of the system are found in the topologically non-trivial phase, dispersing similarly as one-dimensional bulk plasmons in the conventional Su-Schrieffer-Heeger chain. For two-dimensional bulk collective modes, we reveal regimes of enhanced inter-band wave function correlations, leading to characteristic hardening and softening of inter- and intra-band bulk plasmonic branches, respectively. In the two-dimensional Haldane Chern insulator model, chiral, uni-directional edge plasmons in nano-ribbon architectures are observed, which can be characterized by an effective Coulomb interaction cross section. Bulk collective excitations in the two-dimensional Haldane model are shown to be originated by single-particle band structure details in different topological phases.

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Henning Schlömer, Zhihao Jiang, Stephan Haas. 2020-11-19. Plasmons in Two-Dimensional Topological Insulators. https://doi.org/10.1103/physrevb.103.115116

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