半径梯度变化的一维量子点阵列实现的石墨烯电子超构表面

doi:10.3969/j.issn.1000-5641.2025.03.013

摘要/Abstract

摘要：

理论展示了一种用于操控石墨烯弹道电子的新型超构表面. 该超构表面是由多个周期排列的复原胞组成的一维门控量子点阵列, 其中每个复原胞由半径梯度变化的一组门控量子点组成, 且施加在所有门控量子点上的偏压相同. 严格的米氏散射理论和多重散射理论揭示了, 由不同复原胞组成的超构表面能够使入射电子波以近100%效率发生不同角度的偏转, 从而达到控制电子传输的目的. 该超构表面相当紧凑, 波前整形能够在远低于电子室温弹道输运距离的范围内完成. 以这种超构表面为基础发展的电子光学元件, 其尺寸将大幅减少. 这为电子光学摆脱对低温条件的依赖, 发展更加实用的室温石墨烯电子光学技术提供了解决方案.

关键词: Dirac费米子, 量子点阵列, 多重散射理论, 电子超构表面

Abstract:

We theoretically demonstrate a novel metasurface for graphene ballistic electrons, which is a one-dimensional gate-defined quantum-dot array comprising multiple complex unit cells arranged periodically. Each complex unit cell is composed of a set of quantum dots with gradient-varying radii. The same bias is applied to all the quantum dots. The rigorous Mie scattering theory and multiple scattering theory reveal that the metasurfaces comprising different complex unit cells can deflect the incident electron wave at different angles with almost 100% efficiency, thus demonstrating high control over the transport of graphene electrons. The ultracompactness of the metasurface enables it to shape the wavefront within a distance significantly smaller than the room-temperature ballistic-transport distance. Electron optics devices can be miniaturized considerably by adopting the metasurface, thus providing a solution for eliminating low-temperature conditions and developing room-temperature electron optics technologies with significant application potential in graphene.

Key words: Dirac fermion, quantum dot array, multiple scattering theory, electron metasurfaces

中图分类号:

O412

童欣, 杜骏杰. 半径梯度变化的一维量子点阵列实现的石墨烯电子超构表面[J]. 华东师范大学学报（自然科学版）, 2025, 2025(3): 109-115.

Xin TONG, Junjie DU. Graphene electron metasurfaces realized using one-dimensional array of quantum dots with gradient-varying radii[J]. J* E* C* N* U* N* S*, 2025, 2025(3): 109-115.

图/表 4

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表1

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$\varGamma$/nm	${\theta }_{\rm{actu}}$/(°)	${\theta }_{\rm{calc}}$/(°)
96	40.6	40.5
120	31.1	31.6
144	25.8	25.9
168	21.0	22.0
192	18.9	19.1
216	17.4	16.2

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