Ab-initio piezoresistivity and intervalley scattering in n-Si

The relative contribution of f- and g-type intervalley scattering processes in Si, corresponding to scattering to inequivalent and equivalent valleys, respectively, has been a topic of debate for many decades. Although typical transport properties are not able to distinguish these processes, the piezoresistivity and the diffusion coefficient are notable exceptions. Ab-initio calculations of such properties provide a means to resolve this controversy, but the computed transport properties of Si under uniaxial stress have not been extensively reported. Here, we calculate the piezoresistivity and diffusion coefficient of Si from first principles at various temperatures and crystallographic orientations. The calculations and comparison with experiment allow for the relative contribution of f- and g-type intervalley scattering to be rigorously assessed.