A concept of spin plasmon, a collective mode of spin-density, in strongly correlated electron systems has been proposed since the 1930s. It is expected to bridge between spintronics and plasmonics by strongly confining the photon energy in the subwavelength scale within single magnetic-domain to enable further miniaturizing devices. However, spin plasmon in strongly correlated electron systems is yet to be realized. Herein, we present a new spin correlated-plasmon at room temperature in novel Mott-like insulating highly oriented single-crystalline gold quantum-dots (HOSG-QDs). Interestingly, the spin correlated-plasmon is tunable from the infrared to visible, accompanied by spectral weight transfer yielding a large quantum absorption midgap state, disappearance of low-energy Drude response, and transparency. Supported with theoretical calculations, it occurs due to an interplay of surprisingly strong electron–electron correlations, s–p hybridization and quantum confinement in the s band. The first demonstration of the high sensitivity of spin correlated-plasmon in surface-enhanced Raman spectroscopy is also presented.

中文翻译：

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新型高度定向单晶金量子点中的新自旋相关等离子体

自 1930 年代以来，在强相关电子系统中提出了自旋等离子体的概念，即自旋密度的集体模式。通过将亚波长范围内的光子能量强烈限制在单个磁畴内，有望在自旋电子学和等离子体激元之间架起桥梁，从而使设备进一步小型化。然而，强相关电子系统中的自旋等离子体尚未实现。在此，我们在新型莫特状绝缘高度取向的单晶金量子点（HOSG-QD）中在室温下提出了一种新的自旋相关等离子体。有趣的是，自旋相关等离子体是从红外到可见光可调的，伴随着光谱权重转移产生大的量子吸收中带隙状态、低能德鲁德响应的消失和透明度。有理论计算支持，它的发生是由于令人惊讶的强电子-电子相关性、s-p 杂化和 s 带中的量子限制的相互作用。还首次展示了表面增强拉曼光谱中自旋相关等离子体的高灵敏度。