Erratum: Highly Anisotropic Dirac Cones in Epitaxial Graphene Modulated by an Island Superlattice [Phys. Rev. Lett.105, 246803 (2010)]

Unraveling the Intrinsic and Robust Nature of van Hove Singularities in Twisted Bilayer Graphene by Scanning Tunneling Microscopy and Theoretical Analysis

“…It has been proposed that periodic potentials with wavelengths in the nanometer range could lead to anisotropic renormalization of the velocity of low energy charge carriers [4] or to the generation of new massless Dirac fermions [5]. Experimental works intended for verifying these theoretical predictions were recently reported [6][7][8], where the periodic perturbation was generated either by a lattice mismatch with the supporting material or by a self-organized array of clusters. An alternative route for modifying graphene's band structure would be to exploit a rotation between stacked graphene layers [9].…”

Optimizing long-range order, band gap, and group velocities for graphene on close-packed metal surfaces

“…For the first system mostly unperturbed Dirac cones at the K-points of the Brillouin zone, except for the opening of minigaps at the boundaries of the mini-Brillouin zone, have been reported [51]. Figure 5 shows STM images and ARPES intensities comparing both systems, revealing that the cluster superlattice potential induces a strong group velocity anisotropy together with a significant band gap opening [29]. We focus on the energy region close to the apex of the Dirac cone, and, since the linear dispersion of the π band is modified close to the Bragg planes, we restrict our analysis to energies E − E F > −0.5 eV.…”

“…We now describe the effect of a periodic potential on the electronic band structure of graphene resulting from the moiré structure of g/Ir(111)-(9.25 × 9.25) [12,15] and from its reinforcement by self-assembled Ir clusters grown on top [29]. For the first system mostly unperturbed Dirac cones at the K-points of the Brillouin zone, except for the opening of minigaps at the boundaries of the mini-Brillouin zone, have been reported [51].…”

“…This re-hybridization is localized at the graphene areas covered by clusters, since only there can one of the two C atoms of the unit cell hybridize with a cluster Ir atom above and the other with a substrate Ir atom below. We show the experimental realization of this concept of band gap engineering for equidistant Ir clusters grown on g/Ir(111) [29]. Alternative methods of inducing band gaps in graphene layers ranging from a few tens to a few hundreds of meV are patterning [30][31][32][33], adsorption [34][35][36] and intercalation of suitable elements [37,38], strain [39] or substrate induced symmetry breaking [40,41].…”

Angle-dependent bandgap engineering in gated graphene superlattices

“…Among the most important characteristic of graphene superlattices we can find: additional Dirac cones in the energy-dispersion relation 26,29,[31][32][33][38][39][40]43 and highly anisotropic propagation of charge carriers. 25,30,31,38 In other words, the miniband structure of a EGS is more intricate than the corresponding one of a conventional superlattice, since the transversal motion cannot be decoupled from the longitudinal one. 24 This is quite interesting, since depending on the transversal wave vector or the angle of the electrons that impinge on the superlattice structure the propagation properties can be tuned readily.…”