1] Center for Nanoscience and Nanotechnology, School of Physics and Technology, and Institute for Advanced Studies, Wuhan University, Wuhan 430072, China [2] Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany.
Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology (KIT), D-76131 Karlsruhe, Germany.
Nat Commun. 2015 May 27;6:7132. doi: 10.1038/ncomms8132.
The standard hydrodynamic Drude model with hard-wall boundary conditions can give accurate quantitative predictions for the optical response of noble-metal nanoparticles. However, it is less accurate for other metallic nanosystems, where surface effects due to electron density spill-out in free space cannot be neglected. Here we address the fundamental question whether the description of surface effects in plasmonics necessarily requires a fully quantum-mechanical ab initio approach. We present a self-consistent hydrodynamic model (SC-HDM), where both the ground state and the excited state properties of an inhomogeneous electron gas can be determined. With this method we are able to explain the size-dependent surface resonance shifts of Na and Ag nanowires and nanospheres. The results we obtain are in good agreement with experiments and more advanced quantum methods. The SC-HDM gives accurate results with modest computational effort, and can be applied to arbitrary nanoplasmonic systems of much larger sizes than accessible with ab initio methods.
标准的含硬壁边界条件的流体动力学 Drude 模型可以对贵金属纳米粒子的光学响应进行准确的定量预测。然而，对于其他金属纳米系统，由于自由空间中电子密度溢出引起的表面效应不能被忽略，该模型的准确性就会降低。在这里，我们提出了一个基本问题，即等离子体表面效应的描述是否一定需要全量子力学从头计算方法。我们提出了一种自洽的流体动力学模型（SC-HDM），可以用它来确定非均匀电子气的基态和激发态性质。利用该方法，我们能够解释 Na 和 Ag 纳米线和纳米球的尺寸相关的表面共振位移。我们得到的结果与实验和更先进的量子方法吻合得很好。SC-HDM 以适度的计算工作量就能得到准确的结果，并且可以应用于比从头计算方法更能处理的任意纳米等离子体系统。
