The development of nanoplasmonic devices, such as plasmonic circuits and metamaterial superlenses in the visible to ultraviolet frequency range, is hampered by the lack of low-loss plasmonic media. Recently, strong plasmonic response was reported in a certain class of topological insulators. Here, we present a first-principles density functional theory analysis of the dielectric functions of topologically insulating quaternary (Bi,Sb)₂(Te,Se)₃ trichalcogenide compounds. Bulk plasmonic properties, dominated by interband transitions, are observed from 2 to 3 eV and extend to higher frequencies. Moreover, trichalcogenide compounds are better plasmonic media than gold and silver at blue and UV wavelengths. By analyzing thin slabs, we also show that these materials exhibit topologically protected surface states, which are capable of supporting propagating plasmon polariton modes over an extremely broad spectral range, from the visible to the mid-infrared and beyond, owing to a combination of inter- and intra-surface band transitions.

缺少低损耗的等离子体介质阻碍了纳米等离子体设备的发展，例如在可见到紫外频率范围内的等离子体电路和超材料超透镜。最近，在某些类型的拓扑绝缘子中报告了强烈的等离子体响应。在这里，我们提出拓扑绝缘四元（Bi，Sb）₂（Te，Se）₃介电函数的第一原理密度泛函理论分析三氯杀螨醇化合物。从2eV到3eV观察到以带间跃迁为主的体等离子体特性，并扩展到更高的频率。此外，在蓝色和紫外线波长下，三卤化钨化合物比金和银是更好的等离子体介质。通过分析薄板，我们还表明，这些材料表现出受拓扑保护的表面状态，由于相互之间的相互影响，它们能够在从可见光到中红外以及更远的光谱范围内支持传播的等离激元极化子模式。 -和表面内带跃迁。