Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 3: Focus Session: Electron-phonon interaction and ultrafast processes in semiconductors
HL 3.3: Topical Talk
Montag, 11. März 2013, 10:15–10:45, H13
Quantum dots - artificial atoms, molecules or small pieces of bulk? Nonadiabatic molecular dynamics in the Kohn-Sham representation. — •Oleg Prezhdo1, Heather Jaeger1, Long Run1, Amanda Neukirch1, and Kim Hyeon-Deuk2 — 1University of Rochester, Rochester, NY, USA — 2Kyoto University, Kyoto, Japan
Quantum dots (QD) are quasi-zero dimensional structures with a unique combination of solid-state and atom-like properties. Unlike bulk or atomic materials, QD properties can be modified continuously by changing QD shape and size. Often, the bulk and atomic viewpoints contradict each other. The atomic view suggests strong electron-hole and charge-phonon interactions, and slow energy relaxation due to mismatch between electronic energy gaps and phonon frequencies. The bulk view advocates that the kinetic energy of quantum confinement is greater than electron-hole interaction, charge-phonon coupling is weak, and relaxation through quasi-continuous bands is rapid. QDs exhibit new physical phenomena: The phonon bottleneck to electron energy relaxation and generation of multiple excitons can improve efficiencies of photovoltaic devices. Our state-of-the-art nonadiabatic molecular dynamics techniques, implemented within time-dependent density functional theory, allow us to model QDs at atomistic level and in time-domain, providing a unifying description of quantum dynamics on the nanoscale.