## Title data

Axt, Vollrath M. ; Victor, K. ; Stahl, Arne:

**Influence of a phonon bath on the hierarchy of electronic densities in an optically excited semiconductor.**

*In:* Physical Review B.
Vol. 53
(1996)
Issue 11
.
- pp. 7244-7258.

ISSN 0163-1829

DOI: https://doi.org/10.1103/PhysRevB.53.7244

## Abstract in another language

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.

## Further data

Item Type: | Article in a journal |
---|---|

Refereed: | Yes |

Keywords: | Excitons; Biexcitons; phonons; density matrix theory; dynamics controlled truncation; semiconductor dynamics; non-linear optics; ultrafast dynamics |

Institutions of the University: | Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III > Chair Theoretical Physics III - Univ.-Prof. Dr. Martin Axt Faculties Faculties > Faculty of Mathematics, Physics und Computer Science Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Theoretical Physics III |

Result of work at the UBT: | No |

DDC Subjects: | 500 Science > 530 Physics |

Date Deposited: | 16 Oct 2017 10:04 |

Last Modified: | 16 Oct 2017 10:04 |

URI: | https://eref.uni-bayreuth.de/id/eprint/40012 |