Plasmons in the van der Waals charge-density-wave material 2H-TaSe(2).
Plasmons in the van der Waals charge-density-wave material 2H-TaSe(2).
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DOI：
10.1038/s41467-020-20720-0
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发表时间：
2021-01-15
影响因子：
16.6
通讯作者：
Yan H
中科院分区：
文献类型：
--
作者：
Song C;Yuan X;Huang C;Huang S;Xing Q;Wang C;Zhang C;Xie Y;Lei Y;Wang F;Mu L;Zhang J;Xiu F;Yan H
石墨烯以外的二维（2D）材料中的等离子体激元最近受到了广泛的关注。然而，由于缺乏合适的材料，实验研究受到限制。在这里，我们实验证明了相关的2D电荷密度波（CDW）材料：2 H-TaSe 2中的局部等离子体激元。等离子体共振可以覆盖从太赫兹（40 μm）到电信（1.55 μm）的宽光谱范围，并且可以通过改变厚度和介电环境来进一步调谐。等离子体激元色散在大波矢处发生突变，这是带间跃迁普遍屏蔽效应的结果。更有趣的是，观察到与CDW激发相关的等离子体共振的异常温度依赖性。在CDW阶段，接近CDW激发频率的等离子体激元峰变得更宽且不对称，模仿两个耦合振荡器。我们的研究不仅揭示了本征屏蔽对二维等离子体激元的普遍作用，而且为二维相关材料中可调谐等离子体激元开辟了一条途径。在这里，2 H-TaSe 2纳米带阵列显示出宽带等离子体响应，可以从太赫兹到电信范围进行调谐。这些局部等离子体激元也可以耦合到电荷密度波激发，提供对2D相关材料中等离子体激元激发物理的见解。
Plasmons in two-dimensional (2D) materials beyond graphene have recently gained much attention. However, the experimental investigation is limited due to the lack of suitable materials. Here, we experimentally demonstrate localized plasmons in a correlated 2D charge-density-wave (CDW) material: 2H-TaSe2. The plasmon resonance can cover a broad spectral range from the terahertz (40 μm) to the telecom (1.55 μm) region, which is further tunable by changing thickness and dielectric environments. The plasmon dispersion flattens at large wave vectors, resulted from the universal screening effect of interband transitions. More interestingly, anomalous temperature dependence of plasmon resonances associated with CDW excitations is observed. In the CDW phase, the plasmon peak close to the CDW excitation frequency becomes wider and asymmetric, mimicking two coupled oscillators. Our study not only reveals the universal role of the intrinsic screening on 2D plasmons, but also opens an avenue for tunable plasmons in 2D correlated materials. Here, arrays of 2H-TaSe2 nanoribbons are shown to exhibit a broadband plasmonic response that can be tuned from THz to telecom range. These localized plasmons can also couple to charge density wave excitations, offering insights on the physics of plasmonic excitations in 2D correlated materials.
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影响因子：
3.7
作者：
Dordevic, SV;Basov, DN;Bucher, E
通讯作者：
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