TY  - JOUR
AU  - Dos Santos, Flaviano José
AU  - Bahamon, Dario A.
AU  - Muniz, Roberto B.
AU  - McKenna, Keith
AU  - Castro, Eduardo V.
AU  - Lischner, Johannes
AU  - Ferreira, Aires
TI  - Impact of complex adatom-induced interactions on quantum spin Hall phases
JO  - Physical review / B
VL  - 98
IS  - 8
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - FZJ-2018-06430
SP  - 081407
PY  - 2018
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000442077800001
DO  - DOI:10.1103/PhysRevB.98.081407
UR  - https://juser.fz-juelich.de/record/857193
ER  -