Song Justin C W, Gabor Nathaniel M
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore, Singapore.
Nat Nanotechnol. 2018 Nov;13(11):986-993. doi: 10.1038/s41565-018-0294-9. Epub 2018 Nov 5.
In recent decades, scientists have developed the means to engineer synthetic periodic arrays with feature sizes below the wavelength of light. When such features are appropriately structured, electromagnetic radiation can be manipulated in unusual ways, resulting in optical metamaterials whose function is directly controlled through nanoscale structure. Nature, too, has adopted such techniques-for example in the unique colouring of butterfly wings-to manipulate photons as they propagate through nanoscale periodic assemblies. In this Perspective, we highlight the intriguing potential of designer structuring of electronic matter at scales at and below the electron wavelength, which affords a new range of synthetic quantum metamaterials with unconventional responses. Driven by experimental developments in stacking atomically layered heterostructures-such as mechanical pick-up/transfer assembly-atomic-scale registrations and structures can be readily tuned over distances smaller than characteristic electronic length scales (such as the electron wavelength, screening length and electron mean free path). Yet electronic metamaterials promise far richer categories of behaviour than those found in conventional optical metamaterial technologies. This is because, unlike photons, which scarcely interact with each other, electrons in subwavelength-structured metamaterials are charged and strongly interact. As a result, an enormous variety of emergent phenomena can be expected and radically new classes of interacting quantum metamaterials designed.
近几十年来，科学家们已经开发出了制造特征尺寸小于光波长的合成周期性阵列的方法。当这些特征被适当地构建时，电磁辐射可以以不同寻常的方式被操控，从而产生其功能可通过纳米级结构直接控制的光学超材料。自然界也采用了这样的技术——例如蝴蝶翅膀独特的色彩——来在光子通过纳米级周期性组件传播时对其进行操控。在这篇观点文章中，我们强调了在电子波长及以下尺度对电子物质进行设计性构造的有趣潜力，这提供了一系列具有非常规响应的新型合成量子超材料。受堆叠原子层状异质结构的实验进展（如机械拾取/转移组装）的推动，原子尺度的配准和结构可以在小于特征电子长度尺度（如电子波长、屏蔽长度和电子平均自由程）的距离上轻松调整。然而，电子超材料有望展现出比传统光学超材料技术更为丰富多样的行为类别。这是因为，与几乎不相互作用的光子不同，亚波长结构超材料中的电子带有电荷且相互之间存在强烈相互作用。因此，可以预期会出现各种各样的涌现现象，并设计出全新的相互作用量子超材料类别。
