Unconventional plasmonic materials beyond traditional noble metals extend applications of nanotechnology to novel optical, electrical, and magnetic devices. For example, the low photoluminescence (PL) efficiency of two-dimensional (2D) magnetic materials hinders their effective utilization in magnetooptical studies and practical applications, despite their significant role in information storage and spintronic devices. Plasmon-enhanced PL is a promising route toward efficient magneto-optical applications. Here, we report the first observations of enhanced PL and Raman signals in a multilayered 2D antiferromagnet MnPS₃, which are attributed to the near-field edge plasmon antenna enhancement in few hundred nm thick flakes. We observed two in-gap near-infrared emission signals and studied their thickness dependence. For the first time, we performed tip-enhanced photoluminescence (TEPL) imaging of MnPS₃ in classical (tapping mode) and quantum plasmonic (contact mode) regimes. Classical TEPL showed signal enhancement via plasmonic gap-mode and surface guided waves. Quantum plasmonic TEPL showed evidence for edge plasmons in MnPS₃ via tunneling-induced PL suppression, revealing a 300 nm wide edge plasmon size. Our work opens new possibilities for plasmonic applications of MnPS₃, while quantum plasmonic imaging may be used to discover novel plasmonic materials.

中文翻译：

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MnPS3 中边缘等离子体激元的光致发光和拉曼增强

超越传统贵金属的非常规等离子体材料将纳米技术的应用扩展到新型光学、电学和磁学器件。例如，二维（2D）磁性材料的低光致发光（PL）效率阻碍了它们在磁光研究和实际应用中的有效利用，尽管它们在信息存储和自旋电子器件中发挥着重要作用。等离激元增强 PL 是实现高效磁光应用的一条有前途的途径。在这里，我们报告了在多层二维反铁磁体 MnPS ₃中增强的 PL 和拉曼信号的首次观察，这归因于几百 nm 厚的薄片中的近场边缘等离子体天线增强。我们观察了两个间隙内近红外发射信号并研究了它们的厚度依赖性。我们首次在经典（轻敲模式）和量子等离子体（接触模式）模式下对 MnPS ₃进行尖端增强光致发光（TEPL）成像。经典 TEPL 通过等离子体间隙模式和表面导波显示信号增强。量子等离子体 TEPL 通过隧道诱导的 PL 抑制显示了 MnPS ₃中边缘等离子体激元的证据，揭示了 300 nm 宽的边缘等离子体激元尺寸。我们的工作为 MnPS ₃的等离子体应用开辟了新的可能性，而量子等离子体成像可用于发现新型等离子体材料。