A Simple Way to Turn Graphene Topological
Mardi 2 août 2016 15:00
- Duree : 1 heure
Lieu : Salle "Remy Lemaire" K 223 (1er étage) bât. K de l’institut Néel/CNRS
Orateur : Xiao HU (International Center for Materials Nanoarchitectonics (WPI-MANA))
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Honeycomb lattice supports Dirac-type dispersions, a feature important for achieving nontrivial topology. Haldane was the first to derive the quantum anomalous Hall effect by introducing the staggered flux associated with the next-nearest neighbor (NNN) hopping into the tight-bind model, and Kane-Mele discovered the quantum spin Hall effect noticing that the spin-orbital coupling emerges from the NNN hopping. Recently we have revealed that a topological state can be achieved upon tuning the strength of nearest-neighbor (NN) hopping energy on honeycomb lattice. This may open a new way to drive graphene into a topological state protected by a large energy gap. I will also discuss the application of this idea to electromagnetic systems, which makes pure-silicon topological photonics possible.
[1] L.-H. Wu and X. Hu, Phys. Rev. Lett. 114, 223901 (2015).
[2] L.-H. Wu and X. Hu, Sci. Rep. 6, 24347 (2016).
Contact : christoph.groth@cea.fr
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