Graphene has gained a huge interest since it has been illustrated as the first stable 2D crystal [1] [2]. Moreover, graphene is the basic structuring unit for all graphitic material [3]. Since this gapless material has been demonstrated, the main problem that has been investigated is the gap band opening and controlling in the energy spectrum of graphene. A variety of methods have been established to open a gap in graphene’s band, some are based on destroying the honeycomb structure of graphene, where others maintain it. One of the most effective former methods is the application of an external field, which creates atomic sites with different electric potentials. However, this modification is only valid of multi-layered graphene as if a vertical field is applied to a single layer graphene there will be no gap in the band structure as the two sublattices remain equivalent. Hence, there is a demand for effective gap opening methods in single layer graphene that will maintain the high carrier mobility and allow manipulation of Dirac points. This study provides a theoretical analysis to investigate the band structure of single layer graphene in laser field (and graphene superlattices by analogy [4]), and some of its electronic properties. We show that the spectra and the current flow of Dirac electrons in graphene can be controlled by applying linearly polarised laser field to a graphene sheet under the application of static fields (Electric or Magnetic). We demonstrate how Dirac points can be manipulated by altering the laser field parameters based on Floquet theory and the resonance approximation. Electrons’ ac current can be manipulated with a describable intensity.
[1] Novoselov et al. (2004) Electric field effect in atomically thin carbon films, Science 306, 666.[2] Meyer et al. (2007) The structure of suspended graphene sheets, Nature 446, 60. [3] O’Hare et al. (2012) A stable flat form of two- dimensional crystals: could graphene, silicene, germanene be minigap semiconductors, Nano Lett. 12,1045[4] Savel’ev, S. E. and Alexandre, A.S (2011) Massles Dirac fermions in laser field as a counterpart of graphene superlattices, Physical Review B 84, 035428.
