Optical response and excitons in gapped graphene

Optical response and excitons in gapped graphene

Nonlinear Optical Response from Excitons in Soliton Lattice Systems

Exciton eects on conjugated polymers and the resulting optical nonlinearities are investigated in soliton lattice systems. The magnitude of the THG at the 10 percent doping increases by the factor about 10 2 from that of the neutral system. The huge increase by the order two is common for several choices of Coulomb interaction strengths, and is seen in open systems as well as in periodic system...

Supercritical Coulomb Impurities in Gapped Graphene

We study the problem of Coulomb field-induced charging of the ground state in a system of 2D massive Dirac particles – gapped graphene. As in its 3D QED counterpart, the critical Coulomb coupling is renormalized to higher values, compared to the massless case. We find that in gapped graphene a novel supercritical regime is possible, where the screening charge is comparable to the impurity charg...

Thermally activated conductivity in gapped bilayer graphene

This is a theoretical study of electron transport in gated bilayer graphene — a novel semiconducting material with a tunable band gap. It is shown that the quantum mechanical superposition between conduction and valence band states enhances the subgap conductivity and facilitates the thermally activated transport. The mechanism proposed can also lead to the non-monotonic conductivity vs. temper...

Resonant excitation of graphene k-phonon and intra-landau-level excitons in magneto-optical spectroscopy [corrected].

Precise infrared magnetotransmission experiments have been performed in magnetic fields up to 32 T on a series of multilayer epitaxial graphene samples. We observe changes in the spectral features and broadening of the main cyclotron transition when the incoming photon energy is in resonance with the lowest Landau level separation and the energy of a K point optical phonon. We have developed a ...