The plasmonic resonance of the free electrons at a metal-topological insulator interface is studied with the application of axion electrodynamics. The additional red-shift due to the axion field previously observed in the literature is accounted for by a mechanical model similar to that used in the hybridization model for coupled plasmonic resonances in metallic nanoshells. Such model sheds light on the origin of the red-shift being caused by the decrease in interaction potential energy for the free electron fluid due to the axion-induced charges at the interface of the metal and the topological insulator.

中文翻译：

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存在拓扑绝缘体时的表面等离子体共振

应用轴子电动力学研究了金属-拓扑绝缘体界面处自由电子的等离子体共振。由于先前在文献中观察到的轴子场引起的额外红移由类似于在金属纳米壳中耦合等离子体共振的杂交模型中使用的机械模型解释。这种模型揭示了红移的起源，这是由于金属和拓扑绝缘体界面处的轴子感应电荷导致自由电子流体的相互作用势能下降。