The creation of energetic electrons through plasmon excitation of nanostructures before thermalization has been proposed for a wide number of applications in optical energy conversion and ultrafast nanophotonics. However, the use of "nonthermal" electrons is primarily limited by both a low generation efficiency and their ultrafast decay. We report experimental and theoretical results on the use of broadband plasmonic nanopatch metasurfaces comprising a gold substrate coupled to silver nanocubes that produce large concentrations of hot electrons, which we measure using transient absorption spectroscopy. We find evidence for three subpopulations of nonthermal carriers, which we propose arise from anisotropic electron-electron scattering within sp-bands near the Fermi surface. The bimetallic character of the metasurface strongly impacts the physics, with dissipation occurring primarily in the gold, whereas the quantum process of hot electron generation takes place in both components. Our calculations show that the choice of geometry and materials is crucial for producing strong ultrafast nonthermal electron components.The creation of energetic electrons through plasmon excitation has implications in optical energy conversion and ultrafast nanophotonics. Here, the authors find evidence for three subpopulations of nonthermal carriers which arise from anisotropic electron-electron scattering near the Fermi surface.

中文翻译：

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超宽带等离子体纳米补丁超表面中热电子的增强生成和各向异性库仑散射。

已经提出在热化之前通过等离子激元纳米结构的激发来产生高能电子，以用于光能转换和超快纳米光子学中的许多应用。但是，“非热”电子的使用主要受到发电效率低及其超快衰减的双重限制。我们报告了使用宽带等离激元纳米面片超颖表面的实验和理论结果，这些超表面包括金基质与银纳米立方体，后者产生大量热电子，我们使用瞬态吸收光谱法对其进行了测量。我们找到了非热载流子的三个子种群的证据，我们提出这是由于费米表面附近的sp波段内的各向异性电子电子散射引起的。超表面的双金属特性极大地影响了物理性质，耗散主要发生在金中，而热电子生成的量子过程发生在这两个分量中。我们的计算表明，几何形状和材料的选择对于产生强大的超快非热电子组件至关重要。通过等离激元激发产生高能电子对光能转换和超快纳米光子学有影响。在这里，作者找到了非热载流子的三个子群的证据，这些子流是由费米表面附近的各向异性电子-电子散射引起的。我们的计算表明，几何形状和材料的选择对于产生强大的超快非热电子组件至关重要。通过等离激元激发产生高能电子对光能转换和超快纳米光子学有影响。在这里，作者找到了非热载流子的三个子群的证据，这些子流是由费米表面附近的各向异性电子-电子散射引起的。我们的计算表明，几何形状和材料的选择对于产生强大的超快非热电子组件至关重要。通过等离激元激发产生高能电子对光能转换和超快纳米光子学有影响。在这里，作者找到了非热载流子的三个子群的证据，这些子流是由费米表面附近的各向异性电子-电子散射引起的。