Near-gate plasmons are a new type of plasma oscillations emerging in homogeneous two-dimensional electron systems where a gate provides partial screening of electron-electron interaction. Here we develop a theory of the near-gate plasmons in van der Waals heterostructures comprising a conducting layer separated by a thin insulator from an uncharged disk-shaped gate. We show that in these structures the near-gate plasmons form gate-size-quantized quasistationary discrete modes even in the collisionless limit. Belonging to continuum spectrum of two-dimensional plasmons outside of the disk-gate, the near-gate plasmons are manifested as Fano-like resonances in frequency and magnetodispersions of scattering cross section of the former scattered off the region under the gate. This enables to recover spectrum of the near-gate plasmons in the van der Waals heterostructures using near-field imaging techniques.

中文翻译：

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范德华异质结构中的准稳态近栅极等离子体

近栅极等离子体是在均匀二维电子系统中出现的一种新型等离子体振荡，其中栅极提供电子-电子相互作用的部分屏蔽。在这里，我们开发了范德华异质结构中的近栅极等离子体激元理论，该异质结构包括由薄绝缘体与不带电的盘状栅极隔开的导电层。我们表明，在这些结构中，即使在无碰撞极限下，近门等离子体激元也能形成门尺寸量化的准稳态离散模式。属于盘门外二维等离子体的连续谱，近门等离子体表现为频率的类 Fano 共振和前者散射截面的磁色散从门下区域散射。