Knox Craig S, Vaughan Matthew T, Fox Nathan R, Yagmur Ahmet, Sasaki Satoshi, Cunningham John E, Linfield Edmund H, Davies Alexander G, Freeman Joshua R
School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UK.
School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
Nanophotonics. 2024 Feb 5;13(10):1843-1850. doi: 10.1515/nanoph-2023-0690. eCollection 2024 Apr.
We have performed an investigation into the optical conductivity and magnetotransport properties of top-gated devices patterned on the topological insulator BiSe in order to determine the relative effects of the different carrier species that exist within these novel materials. We find that the topologically protected surfaces within our samples are partially screened from the action of the gate by trivial band-bending states formed at the top surface of the topological insulator. Despite this, the mobility of the topological surface carriers is significantly affected by the application of an external gate bias. Additionally, we find that the optical conductivity response is dominated by the topologically protected surface states, and that the optical conductivity is particularly sensitive to the scattering caused by the topological surfaces coupling to trivial states, arising from the bulk or band-bending induced surface states. These results will have interesting applications to the design of future plasmonic devices that incorporate topological materials.
我们对在拓扑绝缘体BiSe上制备的顶栅器件的光导率和磁输运性质进行了研究，以确定这些新型材料中不同载流子种类的相对影响。我们发现，样品中的拓扑保护表面会被拓扑绝缘体顶表面形成的平凡能带弯曲态部分屏蔽，从而免受栅极作用的影响。尽管如此，施加外部栅极偏压会显著影响拓扑表面载流子的迁移率。此外，我们发现光导率响应主要由拓扑保护表面态主导，并且光导率对由拓扑表面与平凡态耦合引起的散射特别敏感，这些平凡态源于体材料或能带弯曲诱导的表面态。这些结果将在未来包含拓扑材料的等离子体器件设计中具有有趣的应用。
