Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 40: Quantum dots and wires: Optical properties III
HL 40.2: Vortrag
Donnerstag, 30. März 2006, 11:15–11:30, POT 151
Quantum kinetics of polarons in semiconductor quantum dots — •Jan Seebeck1, Paul Gartner1,2, and Frank Jahnke1 — 1Institute for Theoretical Physics, University of Bremen, Germany — 2National Institute for Materials Physics, Bucharest-Magurele, Romania
Applications of semiconductor quantum dots (QDs) require efficient carrier scattering processes. We investigate the interaction of carriers with LO phonons in semiconductor QDs, which dominates at low carrier densities and elevated temperatures and leads to fast scattering channels even in QDs where the level spacing does not match the LO-phonon energy.
A quantum kinetic theory of the interacting many-body system is presented, where carriers are described as polarons. The relaxation of a nonequilibrium carrier distribution due to optical pulse excitation is investigated within the full 2-time Green’s function formalism and a 1-time approximation using the generalized Kadanoff-Baym ansatz.
It is shown that the 2-time approach leads to a thermalization in terms of the Kubo-Martin-Schwinger condition, while the 1-time approach fails in the intermediate-coupling regime, event though a steady state carrier distribution is obtained.