Experimental investigation of the vibrational density of states and electronic excitations in metallic nanocrystals
Experimental investigation of the vibrational density of states and electronic excitations in metallic nanocrystals
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DOI：
10.1103/physrevb.89.195402
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发表时间：
2014-05-05
影响因子：
3.7
通讯作者：
Carles, R.
中科院分区：
文献类型：
--
作者：
Bayle, M.;Benzo, P.;Carles, R.
利用拉曼散射技术研究了银纳米晶体的振动态密度。为了同时利用光谱和空间局域表面等离子体共振、光学放大和暗场光谱，采用了特定的样品结构、设置配置和原始的精加工工艺。对原子振动和电子空穴激发（即表面增强拉曼散射中的所谓“背景”）的贡献进行了解纠缠。将提取的VDOS与原子尺度模拟得到的理论VDOS进行了比较。分析了尺寸、应变和无序度对VDOS的影响；特别地，利用几何相分析和高分辨率透射电镜对应变效应进行了实验研究。这项工作提供了一个在纳米尺度上研究热力学性质的机会，比如比热。
An investigation of the vibrational density of states (VDOS) in silver nanocrystals is performed using Raman scattering. A specific sample architecture, setup configuration, and original elaboration process are used in order to take simultaneously advantage of spectrally and spatially localized surface plasmon resonance, optical amplification, and dark-field spectroscopy. Disentangling the contributions of atom vibrations and electron-hole excitations (i.e., the so-called "background" in surface-enhanced Raman scattering) is performed. The extracted VDOS is successfully compared with theoretical ones obtained by atomic scale simulations. The effects of size, strain, and disorder on the VDOS are analyzed; in particular, the strain effect is investigated experimentally using the geometrical phase analysis coupled with high-resolution transmission electron microscopy. This work offers an opportunity to examine thermodynamic properties, like specific heat, at the nanoscale.