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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Impact of complex adatom-induced interactions on quantum spin Hall phases

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dos Santos, Flaviano Jose [1, 2, 3, 4] ; Bahamon, Dario A. [5] ; Muniz, Roberto B. [6] ; McKenna, Keith [7] ; Castro, Eduardo V. [8, 9] ; Lischner, Johannes [10, 11, 12] ; Ferreira, Aires [7]
Total Authors: 7
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[1] Forschungszentrum Julich, Inst Adv Simulat, D-52425 Julich - Germany
[2] Forschungszentrum Julich, Peter Grunberg Inst, D-52425 Julich - Germany
[3] JARA, D-52425 Julich - Germany
[4] Rhein Westfal TH Aachen, D-52056 Aachen - Germany
[5] Univ Prebiteriana Mackenzie, MackGraphe Graphene & Nanomat Res Ctr, Rua Consolacao 896, BR-01302907 Sao Paulo, SP - Brazil
[6] Univ Fed Fluminense, Inst Fis, Niteroi, RJ - Brazil
[7] Univ York, Dept Phys, York YO10 5DD, N Yorkshire - England
[8] Univ Lisbon, Inst Super Tecn, CeFEMA, Ave Rovisco Pais, P-1049001 Lisbon - Portugal
[9] Beijing Computat Sci Res Ctr, Beijing 100084 - Peoples R China
[10] Imperial Coll London, Dept Phys, London SW7 2AZ - England
[11] Imperial Coll London, Dept Mat, London SW7 2AZ - England
[12] Imperial Coll London, Thomas Young Ctr Theory & Simulat Mat, London SW7 2AZ - England
Total Affiliations: 12
Document type: Journal article
Source: Physical Review B; v. 98, n. 8 AUG 17 2018.
Web of Science Citations: 2

Adsorbate engineering offers a seemingly simple approach to tailor spin-orbit interactions in atomically thin materials and thus to unlock the much sought-after topological insulating phases in two dimensions. However, the observation of an Anderson topological transition induced by heavy adatoms has proved extremely challenging despite substantial experimental efforts. Here, we present a multiscale approach combining advanced first-principles methods and accurate single-electron descriptions of adatom-host interactions using graphene as a prototypical system. Our study reveals a surprisingly complex structure in the interactions mediated by random adatoms, including hitherto neglected hopping processes leading to strong valley mixing. We argue that the unexpected intervalley scattering strongly impacts the ground state at low adatom coverage, which would provide a compelling explanation for the absence of a topological gap in recent experimental reports on graphene. Our conjecture is confirmed by real-space Chern number calculations and large-scale quantum transport simulations in disordered samples. This resolves an important controversy and suggests that a detectable topological gap can be achieved by increasing the spatial range of the induced spin-orbit interactions on graphene, e.g., using nanoparticles. (AU)

FAPESP's process: 12/50259-8 - Graphene: photonics and opto-electronics: UPM-NUS collaboration
Grantee:Antônio Hélio de Castro Neto
Support type: Research Projects - SPEC Program