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

Abdulhakim Bake; Qi Zhang; Cong Son Ho; Grace L Causer; Weiyao Zhao; Zengji Yue; Alexander Nguyen; Golrokh Akhgar; Julie Karel; David Mitchell; Zeljko Pastuovic; Roger Lewis; Jared H Cole; Mitchell Nancarrow; Nagarajan Valanoor; Xiaolin Wang; David Cortie

doi:10.1038/s41467-023-37102-x

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

Nat Commun. 2023 Mar 27;14(1):1693. doi: 10.1038/s41467-023-37102-x.

Authors

Abdulhakim Bake^#^{1

2}, Qi Zhang^#^{2

3}, Cong Son Ho⁴, Grace L Causer⁵, Weiyao Zhao^{1

2}, Zengji Yue^{6

7}, Alexander Nguyen^{2

8}, Golrokh Akhgar^{2

8}, Julie Karel^{2

8}, David Mitchell⁹, Zeljko Pastuovic¹⁰, Roger Lewis⁷, Jared H Cole^{2

4}, Mitchell Nancarrow⁹, Nagarajan Valanoor^{2

3}, Xiaolin Wang^{1

2}, David Cortie^{11

12

13}

Affiliations

¹ Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong, NSW, 2522, Australia.
² The Australian Research Council Centre for Excellence in Future Low Energy Electronics Technologies, Wollongong, Sydney, Melbourne, Australia.
³ School of Materials Science and Engineering, The University of New South Wales, Kensington, NSW, 2052, Australia.
⁴ Chemical and Quantum Physics, School of Science, RMIT University, Melbourne, Australia.
⁵ Physics Department, Technical University of Munich, 85748, Garching, Germany.
⁶ Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai, 200093, China.
⁷ School of Physics, Faculty of Engineering and Information Science, University of Wollongong, Wollongong, 2522, NSW, Australia.
⁸ Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia.
⁹ Electron Microscopy Centre, University of Wollongong, Wollongong, NSW, 2522, Australia.
¹⁰ The Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW, 2234, Australia.
¹¹ Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong, Wollongong, NSW, 2522, Australia. dcortie@uow.edu.au.
¹² The Australian Research Council Centre for Excellence in Future Low Energy Electronics Technologies, Wollongong, Sydney, Melbourne, Australia. dcortie@uow.edu.au.
¹³ The Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW, 2234, Australia. dcortie@uow.edu.au.

^# Contributed equally.

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.

Abstract

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