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Pure dephasing and phonon dynamics in GaAs- and GaN-based quantum dot structures : Interplay between material parameters and geometry

Titelangaben

Krummheuer, B. ; Axt, Vollrath Martin ; Kuhn, Tilmann ; D'Amico, I. ; Rossi, F.:
Pure dephasing and phonon dynamics in GaAs- and GaN-based quantum dot structures : Interplay between material parameters and geometry.
In: Physical Review B. Bd. 71 (2005) Heft 23 . - 235329.
ISSN 0163-1829
DOI: https://doi.org/10.1103/PhysRevB.71.235329

Angaben zu Projekten

Projektfinanzierung: Deutsche Forschungsgemeinschaft
European Commission within the Future and Emerging Technologies (FET) project Semiconductor-based implementation of quantum information devices.

Abstract

The pure dephasing of excitons in quantum dot structures due to their interaction with acoustic phonons as well as the spatiotemporal dynamics of the created nonequilibrium phonon population is studied theoretically. The theory is applied to GaAs- as well as GaN-based heterostructures. A detailed analysis of the interplay between different material parameters, different quantum dot geometries, and different electric fields is presented. The optical polarization induced by an ultrashort laser pulse exhibits a characteristic nonexponential behavior: it decays on a pico- or subpicosecond time scale to a value that strongly depends on temperature, structure, and material parameters and is then retained until, on a typically much longer time scale, it finally decays because of electron-hole recombination or transitions to other states. We find that, in general, the remnant optical polarization is much higher in the GaAs-based structures than in the GaN-based structure mainly because of the strongly enhanced piezoelectric coupling in GaN quantum dots. The optical excitation also leads to the buildup of a phonon population consisting of a polaron part that remains localized in the region of the quantum dot and a traveling part that leaves the dot region at the speed of sound. This traveling part exhibits characteristic anisotropies reflecting both the anisotropy of the quantum dot structure and of the coupling matrix elements.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Keywords: quantum dot; generating functions; non-linear optics; ultrafast dynamics; pure dephasing; phonons; analytical solutions; excitons; polaron formation; Non-perturbative solution; decoherence; dephasing; excitons; non-Markovian dynamics; GaN dots; GaAs dots; phonon wave packets; piezoelectric dot-phonon coupling; anisotropic phonon propagation
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: 23 Okt 2017 11:05
Letzte Änderung: 02 Aug 2023 12:59
URI: https://eref.uni-bayreuth.de/id/eprint/40124