Raman spectroscopy as probe of nanometer-scale strain variations in   graphene
  Confocal Raman spectroscopy is a versatile, non-invasive investigation tool and a major workhorse for graphene characterization. Here we show that the experimentally observed Raman 2D line width is a measure of nanometer-scale strain variations in graphene. By investigating the relation between the G and 2D line at high magnetic fields we find that the 2D line width contains valuable information on nanometer-scale flatness and lattice deformations of graphene, making it a good quantity for classifying the structural quality of graphene even at zero magnetic field. 
Christoph Neumann, Sven Reichardt, Pedro Venezuela, Marc Dr\"ogeler,   Luca Banszerus, Michael Schmitz, Kenji Watanabe, Taka...
cond-mat.mes-hall