Unusually strong temperature dependence of graphene electron mobility

We report unusually strong temperature dependence of graphene electron mobility, obtained using full-band Monte Carlo (MC) simulations and experiment. The electron-phonon scattering limited intrinsic graphene electron mobility changes by as much as the fourth power of temperature, Tⁿ (2 < n < 4), in the 200 K to 350 K range. This is in contradiction with the generally observed approximately linear T dependence around room temperature. This linear dependence arises due to the phonon equipartition approximation that gives rise to a linear temperature versus scattering rate relation. The highly nonlinear temperature dependence is reminiscent of transport in the Bloch-Gruneisen temperature range, where phonon energies assisting emissions and absorptions are less than or comparable to thermal energies. In addition, graphene has a conic dispersion relation around its K points or conduction band minima, setting it apart from other materials with parabolic energy-momentum curves around their conduction band minima, and consequently well-defined effective masses.