Plasmons in MoS2 studied via experimental and theoretical correlation of energy loss spectra
Plasmons in MoS2 studied via experimental and theoretical correlation of energy loss spectra
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DOI：
10.1111/jmi.12900
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发表时间：
2020-06-10
影响因子：
2
通讯作者：
Bangert, Ursel
中科院分区：
文献类型：
--
作者：
Moynihan, Eoin;Rost, Stefan;Bangert, Ursel
本文对单层和少层二硫化钼的电子能量损失谱进行了初步的研究。单层MoS 2的介电函数的实验光谱相比，给出明确的标准，不同的信号的性质。Kramers-Kronig分析允许从实验数据中直接提取介电函数。然而，该分析对数据预处理的标准化步骤中的轻微变化敏感。密度泛函理论提供了模拟的介电函数的比较和实验结果的验证。模拟和实验光谱进行比较，以隔离的PI和PI +西格玛表面等离子体模式在单层二硫化钼。单粒子激发掩盖了单层光谱中的等离子体激元，动量分辨测量表明，由于实验中使用的大会聚角和收集角，间接激发了带间跃迁。Lay Description二维材料为更小、更高效的器件提供了一条前进的道路。它们的光学和电子特性超过了摩尔定律所设定的极限。等离子体激元是电子的集体振荡，可以将光限制在比其波长小得多的尺寸。在这项工作中，我们探讨了等离子体性质的MoS 2，一个代表性的候选人从家庭的二维材料被称为过渡金属dichalcogenides.High分辨率电子显微镜和光谱学提供见解的等离子体性质的MoS 2下降到原子尺度。实验结果给出了等离子体激元与电子能量损失谱带间跃迁的关系。密度泛函理论为实验结果提供了理论支持，并对基本物理学提供了评论。
This paper takes a fundamental view of the electron energy loss spectra of monolayer and few layer MoS2. The dielectric function of monolayer MoS2 is compared to the experimental spectra to give clear criteria for the nature of different signals. Kramers-Kronig analysis allows a direct extraction of the dielectric function from the experimental data. However this analysis is sensitive to slight changes in the normalisation step of the data pretreatment. Density functional theory provides simulations of the dielectric function for comparison and validation of experimental findings. Simulated and experimental spectra are compared to isolate the pi and pi + sigma surface plasmon modes in monolayer MoS2. Single-particle excitations obscure the plasmons in the monolayer spectrum and momentum resolved measurements give indication of indirect interband transitions that are excited due to the large convergence and collection angles used in the experiment.Lay Description Two-dimensional materials offer a path forward for smaller and more efficient devices. Their optical and electronic properties give way to beat the limits set in place by Moore's Law. Plasmon are the collective oscillations of electrons and can confine light to dimensions much smaller than its wavelength. In this work we explore the plasmonic properties of MoS2, a representational candidate from a family of 2D materials known as transition metal dichalcogenides.High resolution electron microscopy and spectroscopy provide insights in the plasmonic properties of MoS2 down to an atomic scale. Experimental results show the relationship between plasmons and interband transitions in the electron energy loss spectrum. Density functional theory provides a theoretical support for the experimental findings and provides commentary on the fundamental underlying physics.