Two-dimensional electronic and vibrational band structure of uniaxially strained graphene from ab initio calculations

We present an in-depth analysis of the electronic and vibrational band structure of uniaxially strained graphene by ab initio calculations. Depending on the direction and amount of strain, the Fermi crossing moves away from the K point. However, graphene remains semimetallic under small strains. The deformation of the Dirac cone near the K point gives rise to a broadening of the 2D Raman mode. In spite of specific changes in the electronic and vibrational band structure the strain-induced frequency shifts of the Raman active E-2g and 2D modes are independent of the direction of strain. Thus, the amount of strain can be directly determined from a single Raman measurement.