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Intermediate stages of surface state formation and collapse of topological protection to transport in Bi2Se3

Banerjee, Abhishek and Rai, Abhishek and Majhi, Kunjalata and Barman, Sudipta Roy and Ganesan, R and Kumar P S, Anil (2017) Intermediate stages of surface state formation and collapse of topological protection to transport in Bi2Se3. In: JOURNAL OF PHYSICS-CONDENSED MATTER, 29 (17).

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Official URL: http://dx.doi.org/10.1088/1361-648X/aa666a


Surface states consisting of helical Dirac fermions have been extensively studied in threedimensional topological insulators. Yet, experiments to date have only investigated fully formed topological surface states (TSS) and it is not known whether preformed or partially formed surface states can exist or what properties they could potentially host. Here, by decorating thin films of Bi2Se3 with nanosized islands of the same material, we show for the first time that not only can surface states exist in various intermediate stages of formation but they exhibit unique properties not accessible in fully formed TSS. These include tunability of the Dirac cone mass, vertical migration of the surface state wave-function and the appearance of mid-gap Rashba-like states as exemplified by our theoretical model for decorated TIs. Our experiments show that an interplay of Rashba and Dirac fermions on the surface leads to an intriguing multi-channel weak anti-localization effect concomitant with an unprecedented tuning of the topological protection to transport. Our work offers a new route to engineer topological surface states involving Dirac-Rashba coupling by nano-scale decoration of TI thin films, at the same time shedding light on the real-space mechanism of surface state formation in general.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Department/Centre: Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Division of Physical & Mathematical Sciences > Physics
Date Deposited: 26 Apr 2017 07:22
Last Modified: 26 Apr 2017 07:22
URI: http://eprints.iisc.ac.in/id/eprint/56631

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