Magneto-optical and optical probes of gapped ground states of graphene

by Dr Sergei G. Sharapov (Sharapov Bogolyubov Institute for Theoretical Physics National Academy of Sciences of Ukraine)

Wednesday 6 Feb 2013, 14:00 → 16:00 Europe/Rome

Aula Careri (Dipartimento di Fisica - Ed. G. Marconi)

It has been found experimentally that under certain conditions, like an appropriate substrate, a gap of the order of 10 meV can be opened at the Dirac point of graphene. We demonstrate that opening of such a gap can result in the appearance of a giant fingerprint bump of the Seebeck signal when the chemical potential approaches the gap edge. We have also studied the influence on longitudinal and transverse optical conductivities of bilayer graphene of different kinds of gaps, due to a bias electric field or to a time-reversal symmetry breaking TRSB . We show that two TRSB states can be distinguished by analyzing the dependence of the optical Hall conductivity on the energy of photon. Thes TRSB tates are expected to be observed experimentally via optical polarization rotation either in the Faraday or Kerr effects. We analyzed a possibility of a such experiment for a free standing graphene, graphene on a thick substrate and graphene on a double-layer substrate.