1211.0147 (Andrea Marini)

Competition between the electronic and phonon-mediated scattering
channels in the out-of-equilibrium carrier dynamics of semiconductors: an
ab-initio approach    [PDF]

Andrea Marini

The carrier dynamics in bulk Silicon, a paradigmatic indirect gap semiconductor, is studied by using the Baym-Kadanoff equations. Both the electron--electron(e-e) and electron--phonon(e-p) self--energies are calculated fully ab-initio by using a semi-static GW approximation in the e-e case and a Fan self-energy in the e-p case. By using the generalized Baym-Kadanoff ansatz the two-time evolution is replaced by the only dynamics on the macroscopic time axis. The enormous numerical difficulties connected with a real-time simulation of realistic systems is overcame by using a completed collision approximation that further simplifies the memory effects connected to the time evolution. The carrier dynamics is shown to reduce in such a way to have stringent connections to the well-known equilibrium electron-electron and electron-phonon self-energies. This link allows to use general arguments to motivate the relative balance between the e-e and e-p scattering channels on the basis of the carrier energies.

View original: http://arxiv.org/abs/1211.0147