Effect of electrostatic screening due to non-equilibrium carriers on the lattice scattering rate at low temperatures

The intravalley acoustic scattering rate has been calculated here taking the screening by non-equilibrium electrons into account under the condition when the lifetime of the electrons is controlled by shallow attractive traps at low lattice temperature. The scattering rates now turn out to be field dependent and the characteristics are significantly different from what follows when the electron ensemble is in equilibrium with the lattice. The results indicate the possibility of interesting non-ohmic transport characteristics under these conditions. Numerical results are obtained for high purity samples of Si.

► Perturbation potential in a semiconductor may be screened by carriers.
► High electric field at low temperatures changes screening length.
► Thus matrix elements for electronic transition become field dependent.
► Screening results in a field dependent intravalley acoustic scattering rate.
► Scattering rates significantly changed from what follows for zero field.