金属纳米间隙中太赫兹隧穿的机械调控

中文摘要 AI 辅助

金属纳米间隙将太赫兹（THz）场集中到深亚波长体积中，并在绝缘势垒变得足够窄时支持场驱动电子隧穿。在此，我们展示了在柔性纳米间隙超表面中对隧穿介导的非线性太赫兹透射的机械控制。该超表面由沉积在聚对苯二甲酸乙二醇酯基底上的Au/PMMA/Au纳米间隙组成，通过宏观弯曲实现间隙几何形状的连续调谐。在平坦状态下，共振透射对入射太赫兹场强度仅表现出微弱的依赖性。弯曲后，增大入射场强度会引发显著的共振抑制，同时伴随纳米间隙两端电压的饱和。这种非线性响应与通过机械变窄的PMMA势垒开启场依赖的隧穿导电通道一致。Simmons模型计算表明，当局部间隙宽度接近几纳米范围时，隧穿电流密度显著增加，并伴随相关的耗散间隙响应。这些结果确立了机械变形作为控制柔性超表面中隧穿介导太赫兹非线性的宏观手段。

英文摘要

Metallic nanogaps concentrate terahertz (THz) fields into deep subwavelength volumes and support field-driven electron tunneling when the insulating barrier becomes sufficiently narrow. Here, we demonstrate mechanical control of tunneling-mediated nonlinear THz transmission in a flexible nanogap metasurface. The metasurface consists of Au/PMMA/Au nanogaps fabricated on a polyethylene terephthalate substrate, enabling continuous tuning of the gap geometry through macroscopic bending. In the flat state, the resonant transmission exhibits only a weak dependence on the incident THz field strength. Upon bending, increasing the incident field strength induces pronounced resonance suppression accompanied by saturation of the voltage developed across the nanogaps. This nonlinear response is consistent with the opening of a field-dependent tunneling conduction channel through the mechanically narrowed PMMA barriers. Simmons-model calculations illustrate the strong increase in tunneling current density and the associated dissipative gap response as the local gap width approaches the few-nanometer regime. These results establish mechanical deformation as a macroscopic means of controlling tunneling-mediated THz nonlinearities in flexible metasurfaces.

发表机构

• Ulsan National Institute of Science and Technology (UNIST)（蔚山科学技术院）
• Max Planck Institute for the Structure and Dynamics of Matter（马普物质结构与动力学研究所）
• Incheon National University（仁川国立大学）
• Mohammed VI Polytechnic University（穆罕默德六世理工学院）

机构由 AI 辅助整理，请以论文原文为准。