Li ZheAn, Xu ChunKai, Liu WenJie, Li Meng, Chen XiangJun
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, 230026, China.
Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, 230026, China.
Sci Rep. 2018 Apr 4;8(1):5626. doi: 10.1038/s41598-018-24065-z.
Nonlinear electron scattering is a recently-discovered physical process observed during the localized plasmonic excitation of Ag nanostructures on graphite surface. In the present work, nonlinear electron scattering phenomena is experimentally verified on Au nanostructures by measuring inelastic scattering of electrons field-emitted from tungsten tip. The relative intensity of the electron-energy-loss peak associated with the plasmonic excitation of Au shows again to increase nonlinearly with the electric field generated by the tip-sample bias, demonstrating the generality of nonlinear electron scattering process in plasmonic system. Compared to the nonlinear electron scattering phenomena observed on Ag nanostructures, the nonlinear term for Au nanostructures is about 1 to 2 orders of magnitude smaller, which is in consistent with the field enhancement factor of Au and Ag nanostructures from both the surface-enhanced Raman spectroscopy experiments and the theoretical calculations.
非线性电子散射是最近发现的一种物理过程，在石墨表面银纳米结构的局域等离子体激元激发过程中被观测到。在本工作中，通过测量从钨针尖场发射的电子的非弹性散射，在金纳米结构上对非线性电子散射现象进行了实验验证。与金等离子体激元激发相关的电子能量损失峰的相对强度再次显示出随针尖 - 样品偏压产生的电场呈非线性增加，这证明了等离子体系统中非线性电子散射过程的普遍性。与在银纳米结构上观测到的非线性电子散射现象相比，金纳米结构的非线性项小约1至2个数量级，这与表面增强拉曼光谱实验和理论计算中金银纳米结构的场增强因子一致。
