Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 3: Focus Session: Electron-phonon interaction and ultrafast processes in semiconductors

HL 3.5: Topical Talk

Monday, March 11, 2013, 11:00–11:30, H13

Out-of-equilibrium carrier dynamics in semiconductors: a novel approach — •Andrea Marini — Istituto di Struttura della Materia of the National Research Council, Via Salaria Km 29.3, I-00016 Monterotondo Stazione, Italy — European Theoretical Spectroscopy Facilities (ETSF)

In this talk I will present a novel approach based on the merging of Non-Equilibrium Green’s function theory and Density Functional Theory to investigate the carrier dynamics following a pump excitation.

The case of 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 overcomed 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.