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Tunable spin–orbit coupling and symmetry-protected edge states in graphene/WS_2

Yang, Bowen and Tu, Min-Feng and Kim, Jeongwoo and Wu, Yong and Wang, Hui and Alicea, Jason and Wu, Ruqian and Bockrath, Marc and Shi, Jing (2016) Tunable spin–orbit coupling and symmetry-protected edge states in graphene/WS_2. 2D Materials, 3 (3). Art. No. 031012. ISSN 2053-1583. doi:10.1088/2053-1583/3/3/031012.

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We demonstrate clear weak anti-localization (WAL) effect arising from induced Rashba spin–orbit coupling (SOC) in WS_2-covered single-layer and bilayer graphene devices. Contrary to the uncovered region of a shared single-layer graphene flake, WAL in WS_2-covered graphene occurs over a wide range of carrier densities on both electron and hole sides. At high carrier densities, we estimate the Rashba SOC relaxation rate to be ~0.2 ps^(-1) and show that it can be tuned by transverse electric fields. In addition to the Rashba SOC, we also predict the existence of a'valley-Zeeman' SOC from first-principles calculations. The interplay between these two SOC's can open a non-topological but interesting gap in graphene; in particular, zigzag boundaries host four sub-gap edge states protected by time-reversal and crystalline symmetries. The graphene/WS_2 system provides a possible platform for these novel edge states.

Item Type:Article
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URLURL TypeDescription Paper
Alicea, Jason0000-0001-9979-3423
Additional Information:© 2016 IOP Publishing. Received 15 July 2016; Accepted 30 August 2016; Published 13 September 2016. We gratefully acknowledge Roger Mong for valuable discussions. This work was supported by the DOE BES award No. DE-FG02-07ER46351 (BY and JS) and award No. DE-FG02-05ER46237 (JW and RW); NSF through grant DMR-1341822 (MT and JA); the Caltech Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation; and the Walter Burke Institute for Theoretical Physics at Caltech. DFT simulations were performed on the U.S. Department of Energy Supercomputer Facility (NERSC).
Group:Institute for Quantum Information and Matter, Walter Burke Institute for Theoretical Physics
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-07ER46351
Department of Energy (DOE)DE-FG02-05ER46237
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
NSF Physics Frontiers CenterUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Walter Burke Institute for Theoretical Physics, CaltechUNSPECIFIED
Issue or Number:3
Record Number:CaltechAUTHORS:20160912-161200262
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Official Citation:Bowen Yang et al 2016 2D Mater. 3 031012
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:70285
Deposited By: Tony Diaz
Deposited On:13 Sep 2016 23:45
Last Modified:11 Nov 2021 04:26

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