Nonlocal and quantum mechanical phenomena in noble metal nanostructures become increasingly crucial when the relevant length scales in hybrid nanostructures reach the few-nanometer regime. In practice, such mesoscopic effects at metal–dielectric interfaces can be described using exemplary surface-response functions (SRFs) embodied by the Feibelman d-parameters. Here we show that SRFs dramatically influence quantum electrodynamic phenomena – such as the Purcell enhancement and Lamb shift – for quantum light emitters close to a diverse range of noble metal nanostructures interfacing different homogeneous media. Dielectric environments with higher permittivities are shown to increase the magnitude of SRFs calculated within the specular-reflection model. In parallel, the role of SRFs is enhanced in noble metal nanostructures characterized by large surface-to-volume ratios, such as thin planar metallic films or shells of core–shell nanoparticles, for which the spill-in of electron wave functions enhances plasmon hybridization. By investigating emitter quantum dynamics close to such plasmonic architectures, we show that decreasing the width of the metal region, or increasing the permittivity of the interfacing dielectric, leads to a significant change in the Purcell enhancement, Lamb shift, and visible far-field spontaneous emission spectrum, as an immediate consequence of SRFs. We anticipate that fitting the theoretically modelled spectra to experiments could allow for experimental determination of the d-parameters.

中文翻译：

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等离子发射体相互作用中的非局域效应

当混合纳米结构中的相关长度尺度达到几纳米范围时，贵金属纳米结构中的非局域和量子力学现象变得越来越重要。在实践中，金属-电介质界面的这种介观效应可以使用由 Feibelman 体现的示例性表面响应函数 (SRF) 来描述d-参数。在这里，我们表明，对于接近连接不同均质介质的各种贵金属纳米结构的量子光发射器，SRF 极大地影响量子电动力学现象，例如珀塞尔增强和兰姆位移。具有较高介电常数的介电环境会增加镜面反射模型中计算的 SRF 的幅度。与此同时，SRF 的作用在具有大表面积与体积比的贵金属纳米结构中得到增强，例如薄的平面金属膜或核壳纳米粒子的壳，其中电子波函数的溢出增强了等离子体杂化。通过研究接近此类等离子体结构的发射极量子动力学，我们表明，减小金属区域的宽度或增加界面电介质的介电常数会导致珀塞尔增强、兰姆位移和可见远场自发的显着变化发射光谱，作为 SRF 的直接结果。我们预计，将理论建模的光谱与实验相拟合可以通过实验确定d-参数。