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Axt, Vollrath Martin ; Victor, K. ; Stahl, Arne:
Influence of a phonon bath on the hierarchy of electronic densities in an optically excited semiconductor.
In: Physical Review B.
Bd. 53
(1996)
Heft 11
.
- S. 7244-7258.
ISSN 0163-1829
DOI: https://doi.org/10.1103/PhysRevB.53.7244
Abstract
The influence of a phonon bath on the dynamics of the many-body density matrices relevant for the nonlinear optical response of semiconductors is studied. It is shown that, as in the phonon-free case, only a finite set of electronic density matrices is needed to describe the optical response in a χ(n) experiment. However, to obtain a closed set of equations of motion on the χ(n) level additional truncation concepts have to be introduced in order to decouple the infinite hierarchy of phonon-assisted density matrices. Relations characteristic of intrinsic systems, that have previously been derived to reduce the number of independent dynamical variables in the phonon-free case, are generalized. While in a coherent system the optical response is completely determined by transition-type variables, under the influence of a phonon bath occupation densities can also become independent dynamical quantities. Numerical results for a simple one-dimensional model are presented. Memory effects and dephasing induced by the electron-phonon coupling are discussed for all χ(3) relevant electronic density matrices. The pump-probe signal for σ+-σ− excitation in the spectral region of the biexciton is analyzed. The respective contributions of two processes for the generation of biexcitons, via two- photon transitions (TPT’s) or from previously generated exciton densities, to the microscopic dynamics are identified. The second process yields a χ(3) signal only due to the coupling to the phonon bath and turns out to contribute considerably less than the TPT under all conditions studied in this paper.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Keywords: | Excitons; Biexcitons; phonons; density matrix theory; dynamics controlled truncation; semiconductor dynamics; non-linear optics; ultrafast dynamics |
| Institutionen der Universität: | Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Theoretische Physik III > Lehrstuhl Theoretische Physik III - Univ.-Prof. Dr. Martin Axt Fakultäten Fakultäten > Fakultät für Mathematik, Physik und Informatik Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Theoretische Physik III |
| Titel an der UBT entstanden: | Nein |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 530 Physik |
| Eingestellt am: | 16 Okt 2017 10:04 |
| Letzte Änderung: | 07 Mär 2022 13:55 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/40012 |