Graphene V: Recent advances in studies of graphene and graphene analogues

We are delighted to presenta collection of 17 research/review articles on grapheme and grapheme analogs covering manydifferent aspects. This special issue ist he fifth in series on graphene, reflecting the continued excitement in grapheme science and more recently, in other 2D materials like MoS2 and BN. Ever since the discovery of graphene, Raman spectroscopy has played a crucial role in non-destructive characterization of the number and quality of the layers, defects and doping induced phonon-renormalization to understand electron–phonon interactions. In thi sissue, resonance Raman studies on twisted bilayer graphene, a two-graphene layer system with a mismatch angle between the two hexagonal-structures, have been included which bring out the role of Umklapp double resonance process and the superlatticeinduced van Hove singularities in the electronic joint density of states and phonon dispersion relation. Saito et al. have reviewed Raman studies of grapheme and carbon nanotubes as a function of gate-induced shift of the Fermi energy. This contribution discusses the electron–phonon interaction not only for the zone-center phonons but also for double resonance processes, involving phonons within the interior of the Brillouin zone. It is also shown that Raman spectroscopy provides informationon electron–electron interaction from the electronic Raman spectra observed in metallic carbon nanotubes.