Projects per year
Abstract
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.
Original language | English |
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Article number | 081407(R) |
Number of pages | 6 |
Journal | Physical Review B |
Volume | 98 |
Issue number | 8 |
DOIs | |
Publication status | Published - 17 Aug 2018 |
Bibliographical note
©2018 American Physical Society. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for detailsKeywords
- GRAPHENE
- ADATOMS
- QUANTUM SPIN HALL EFFECT
- Ab initio
- QUANTUM TRANSPORT
- TOPOLOGICAL PHASE
Projects
- 1 Finished
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Mitigating spin-current relaxation in spin-orbit coupled graphene:
Ferreira, A. (Principal investigator)
1/06/15 → 31/05/18
Project: Research project (funded) › Research