双曲材料与拓扑绝缘体界面处表面波的带隙与局域化
Band Gaps and Localization of Surface Waves at Hyperbolic Material and Topological Insulator Interfaces
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中文总结 AI 辅助
本文针对双曲材料与拓扑绝缘体界面表面波建立分析判据，明确其带隙、传播条件等，结合实例分析损耗影响，为中红外光子结构调控提供设计准则。
中文摘要 AI 辅助
我们针对双曲材料与拓扑绝缘体界面处的表面电磁波建立了分析判据，该分析明确了表面波的传播条件、场穿透深度以及光谱带隙。在无损耗模型中，带边主要由介电衬度决定，而体拓扑耦合仅产生微小偏移和对色散的弱修正。对于结合六方氮化硼（hBN）与硒化铋（Bi₂Se₃）的结构，低介电常数衬底上的薄拓扑绝缘体薄膜可大幅拓宽可及的传播窗口。我们还分析了与硒化铋界面的有损耗钛-硅双曲有效介质，为使复分支结构可见，该损耗计算采用了刻意增强的界面响应，因此仅为说明性结果，而非常规拓扑绝缘体的定量预测。在有损耗情形下，色散关系的根仅当场量满足：远离界面时衰减、沿传播方向一致衰减、穿透深度有限且能量流分布一致时，才对应物理导模；当控制横向衰减的复量趋近平方根分支切割时，会出现表观带隙与跳变。这些结果为中红外光子结构中色散、限域、带隙及传播损耗的调控提供了设计准则。
英文摘要
We develop analytical criteria for surface electromagnetic waves at interfaces between hyperbolic materials and topological insulators. The analysis identifies propagation conditions, field penetration depths, and spectral band gaps. In the lossless model, the band edge is governed primarily by dielectric contrast, while the bulk topological coupling produces only a small shift and a weak correction to the dispersion. For structures combining hexagonal boron nitride with bismuth selenide, a thin topological insulator film on a dielectric substrate with low permittivity can substantially broaden the accessible propagation window. We also analyze a dissipative titanium and silicon hyperbolic effective medium interfaced with bismuth selenide. To make the complex branch structure visible, this lossy calculation uses an intentionally enhanced interface response and is therefore illustrative rather than a quantitative prediction for a conventional topological insulator. In the lossy case, a root of the dispersion relation represents a physical guided mode only when the fields decay away from the interface, attenuate consistently along the propagation direction, have finite penetration depths, and exhibit a consistent energy flow profile. Apparent gaps and jumps can occur when the complex quantities controlling transverse decay approach square root branch cuts. These results provide design guidelines for controlling dispersion, confinement, band gaps, and propagation loss in mid-infrared photonic structures.
发表机构
- National Nuclear Research University MEPhI（国立核研究大学莫斯科工程物理学院）
- University of Arizona（亚利桑那大学）
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