Charge carrier mobility in graphene strain and screening effects: Strain and screening effects

Electron mobility in a strained graphene sheet is investigated within the Born approximation by including three prominent scattering mechanisms, namely, charged impurity scattering, surface roughness (SR) scattering, and interaction with lattice phonons. The unsymmetrical hopping parameters between the nearest neighbor atoms, which emanate from the induced strain, are included in the density of states description. Mobility dependence on chirality along zigzag and armchair orientations is also studied. The static dielectric screening for ionized impurity and SR scattering is included in the simulations. For the SR topology, we have examined graphene with the base substrate as dimethyl sulfoxide and SiO2. Unlike its strained silicon counterpart, simulations reveal a significant drop in graphene's mobility with increasing strain. Mobility anisotropy is confirmed along the principal orientations of zigzag and armchair. Within the framework of this study the prime reason for the drop in mobility is attributed to the change in Fermi velocity due to the strain-induced distortions in the graphene honeycomb lattice.