Browsing by Author "Ho, CS"

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    Top-down patterning of topological surface and edge states using a focused ion beam
    (Springer Nature, 2023-03-27) Bake, A; Zhang, Q; Ho, CS; Causer, GL; Zhao, WY; Yue, ZJ; Nguyen, A; Akhgar, G; Karel, J; Mitchell, DRG; Pastuovic, Z; Lewis, RA; Cole, JH; Nancarrow, M; Wang, XL; Cortie, DL
    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