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Granular topological insulators

Banerjee, Abhishek and Deb, Oindrila and Majhi, Kunjalata and Ganesan, R and Sen, Diptiman and Anil Kumar, PS (2017) Granular topological insulators. In: Nanoscale, 9 (20). pp. 6755-6764. ISSN 2040-3364

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Official URL: https://doi.org/10.1039/c7nr01355h


We demonstrate experimentally that a macroscopic topological insulator (TI) phase can emerge in a granular conductor composed of an assembly of tunnel coupled TI nanocrystals of dimension ∼10 nm × 10 nm × 2 nm. Electrical transport measurements on thin films of Bi2Se3 nanocrystals reveal the presence of decoupled top and bottom topological surface states that exhibit large surface state penetration depths (∼30 nm at 2 K). By tuning the size of the nanocrystals and the couplings between them, this new class of TIs may be readily tuned from a non-topological to a topological insulator phase, that too with designer properties. Paradoxically, this seemingly 'dirty' system displays properties that are closer to an ideal TI than most known single crystal systems, making granular/nanocrystalline TIs an attractive platform for future TI research.

Item Type: Journal Article
Publication: Nanoscale
Publisher: Royal Society of Chemistry
Additional Information: The Copyright of this article belongs to the Authors.
Keywords: Electric insulators; Nanocrystals; Surface states; Crystal system; Electrical transport measurements; Large surfaces; System displays; Topological insulators; Topology
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 02 Jun 2022 04:54
Last Modified: 02 Jun 2022 04:55
URI: https://eprints.iisc.ac.in/id/eprint/72979

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