Single-valley engineering in graphene superlattices
Single-valley engineering in graphene superlattices
The two inequivalent valleys in graphene are protected against long-range scattering potentials due to their large separation in momentum space. In tailored $\sqrt{3}N\ifmmode\times\else\texttimes\fi{}\sqrt{3}N$ or $3N\ifmmode\times\else\texttimes\fi{}3N$ graphene superlattices, these two valleys are folded into $\mathrm{\ensuremath{\Gamma}}$ and coupled by Bragg scattering from periodic adsorption. We find that, for top-site adsorption, strong intervalley …