McCauley Mairi, Ansari Lida, Gity Farzan, Rogers Matthew, Burton Joel, Sasaki Satoshi, Ramasse Quentin, Knox Craig, Hurley Paul K, MacLaren Donald, Moorsom Timothy
SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, UK.
Micronano Electronics Group, Tyndall National Institute, University College Cork, Cork, Republic of Ireland.
Commun Mater. 2025;6(1):166. doi: 10.1038/s43246-025-00886-0. Epub 2025 Jul 29.
Topological Insulators (TIs) present an interesting materials platform for nanoscale, high frequency devices because they support high mobility, low scattering electronic transport within confined surface states. However, a robust methodology to control the properties of surface plasmons in TIs has yet to be developed. Surface doping of TIs with molecules may provide tunable control of the two-dimensional plasmons in BiSe, but exploration of such heterostructures is still at an early stage and usually confined to monolayers. We have grown heterostructures of BiSe/C with exceptional crystallinity. Electron energy loss spectroscopy (EELS) reveals significant hybridisation of states at the interface, despite the expectation for only weak van der Waals interactions, including quenching of 2D plasmons. Momentum-resolved EELS measurements are used to probe the plasmon dispersion, with Density Functional Theory predictions providing an interpretation of results based on interfacial charge dipoles. This work provides growth methodology and characterization of highly crystalline TI/molecular interfaces that can be engineered for plasmonic applications in energy, communications and sensing.
拓扑绝缘体（TIs）为纳米级高频器件提供了一个有趣的材料平台，因为它们在受限的表面态中支持高迁移率、低散射的电子输运。然而，尚未开发出一种可靠的方法来控制拓扑绝缘体中表面等离子体激元的特性。用分子对拓扑绝缘体进行表面掺杂可能会提供对BiSe中二维等离子体激元的可调谐控制，但对这种异质结构的探索仍处于早期阶段，并且通常局限于单层。我们已经生长出具有优异结晶度的BiSe/C异质结构。电子能量损失谱（EELS）揭示了界面处态的显著杂化，尽管预计只有微弱的范德华相互作用，包括二维等离子体激元的猝灭。动量分辨EELS测量用于探测等离子体激元色散，密度泛函理论预测基于界面电荷偶极子对结果进行解释。这项工作提供了可用于能量、通信和传感等等离子体应用的高结晶度拓扑绝缘体/分子界面的生长方法和表征。
