Splitting of the Raman 2D band of graphene subjected to strain

The Raman 2D band-important for the analysis of graphene-shows a splitting for uniaxial strain. The splitting depends on the strength and direction of the applied strain and on the polarization of the incident and outgoing light. We expand the double-resonance Raman model in order to explain the strain direction dependence and the polarization dependence of the splitting. The analysis of this splitting gives distinct insight into the origin of the 2D band. Our prediction of the strain direction and polarization dependence agrees well with recent experiments.