Scanning tunnelling microscope light emission: Finite temperature current noise and over cut-off emission.
Scanning tunnelling microscope light emission: Finite temperature current noise and over cut-off emission.
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DOI：
10.1038/s41598-017-03766-x
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发表时间：
2017-06-14
影响因子：
4.6
通讯作者：
Mitra J
中科院分区：
文献类型：
--
作者：
Kalathingal V;Dawson P;Mitra J
扫描隧道显微镜结发射的光的光谱分布不仅具有其固有的等离子体特征，而且还具有隧道电流的光频波动特征。金-金隧道结的实验光谱显示出强烈的偏置（V b）依赖性，奇怪的是，发射能量高于量子截止（eV b）；随偏置增加而单调衰减的分量。通过建立隧道电流波动功率谱密度的理论模型来解释光谱演化，通过考虑系统中的量子输运，将有限的温度贡献纳入其中。值得注意的是，观察到的过截止发射的衰减被发现与结电导随vb的变化密切相关，并得到了很好的解释。该研究强调了等离子体介导的光发射作为电子系统中高频波动的独特探针的范围，这是等离子体产生和控制的基础。
The spectral distribution of light emitted from a scanning tunnelling microscope junction not only bears its intrinsic plasmonic signature but is also imprinted with the characteristics of optical frequency fluc- tuations of the tunnel current. Experimental spectra from gold-gold tunnel junctions are presented that show a strong bias (V b) dependence, curiously with emission at energies higher than the quantum cut-off (eV b); a component that decays monotonically with increasing bias. The spectral evolution is explained by developing a theoretical model for the power spectral density of tunnel current fluctuations, incorporating finite temperature contribution through consideration of the quantum transport in the system. Notably, the observed decay of the over cut-off emission is found to be critically associated with, and well explained in terms of the variation in junction conductance with V b. The investigation highlights the scope of plasmon-mediated light emission as a unique probe of high frequency fluctuations in electronic systems that are fundamental to the electrical generation and control of plasmons.