Top-down patterning of topological surface and edge states using a focused ion beam

Abstract
The conducting boundary states of topological insulators appear at an interface where the characteristic invariant ℤ2 switches from 1 to 0. These states offer prospects for quantum electronics; however, a method is needed to spatially-control ℤ2 to pattern conducting channels. It is shown that modifying Sb2Te3 single-crystal surfaces with an ion beam switches the topological insulator into an amorphous state exhibiting negligible bulk and surface conductivity. This is attributed to a transition from ℤ2 = 1 → ℤ2 = 0 at a threshold disorder strength. This observation is supported by density functional theory and model Hamiltonian calculations. Here we show that this ion-beam treatment allows for inverse lithography to pattern arrays of topological surfaces, edges and corners which are the building blocks of topological electronics. Open Access This article is licensed under a Creative Commons Attribution 4.0 © Crown Copyright 2023
Description
Keywords
Surfaces, Electrical insulators, Quantum electronics, Crystals, Ion beams, Functional analysis, Hamiltonian function
Citation
Bake, A., Zhang, Q., Ho, C. S., Causer, G. L., Zhao, W., Yue, Z., Nguyen, A., Akhgar, G., Karel, J., Mitchell, D., Pastuovic, Z., Lewis, R., Cole, J. H., Nancarrow, M., Valanoor, N., Wang, X., & Cortie, D. (2023). Top-down patterning of topological surface and edge states using a focused ion beam. Nature Communications, 14(1), 1693. doi:10.1038/s41467-023-37102-x
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