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HL: Fachverband Halbleiterphysik

HL 2: Electronic Structure Theory

HL 2.3: Vortrag

Montag, 14. März 2011, 10:45–11:00, POT 51

Vibrational properties of colloidal quantum dots — •Peng Han and Gabriel Bester — Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany.

To investigate the effects of carrier relaxation and dephasing via electron phonon coupling, the vibrational properties of the III-V semiconductor quantum dots are studied by density-functional perturbation theory (DFPT). Based on our calculation, decreasing the quantum dots diameters from 3.4 to 2.6 nm results in a blue shift of the longitudinal acoustic and optical vibration modes. The surface vibration modes are found to appear in the gap between the acoustic and the optical branches. In addition, the vibrational properties of the InAs/InP core/shell quantum dots are studied by projecting the vibrational eigenmodes onto the core and the shell atoms separately. The longitudinal acoustic modes of the core and shell atoms are found to be merged together, while the other modes remain distinct.