CPM Seminar

Magneto-optical spectroscopy of carbon based materials

Nicolas Ubrig

Laboratoire National des Champs Magnétiques Intenses
CNRS

The discovery of graphene and all graphene-based materials like e.g. carbon nanotubes (which consists of a rolled up sheet of graphene) can be considered as a milestone of nanotechnology. The fascinating feature is the different dimensionality of all this materials although they all have a common unit cell, i.e. the honeycomb lattice. A special highlight in carbon research of the past years was the discovery of massless carriers in graphene and the associated unconventional quantum hall effect. The optical response in the near-infrared can give additional insight about the electronic properties of this peculiar materials. In the first part I will present the results we obtained in magneto-optical spectroscopy on carbon nanotubes in high fields, more precisely on semiconducting nanotubes. With help of photo-luminescence techniques, we will give answer to the dark-bright exciton issue. In addition to this we study the dynamic alignment of carbon nanotubes suspended in an aqueous solution.

In the second part I will compare the magneto-transmission spectra of graphene and graphite up to 60 Tesla. Although both materials are very similar, they show, in particular in the landau level fan-chart, the signature of their respective dimensionality.