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HL: Halbleiterphysik

HL 3: III-V semiconductors I

HL 3.11: Vortrag

Montag, 27. März 2006, 12:45–13:00, POT 51

Atomistic and Continuum Description of Acoustic Phonons in Nanostructures — •Frank Grosse and Roland Zimmermann — Halbleitertheore, Institut für Physik an der Humboldt-Unversität Newtonstr. 15 12489 Berlin

Acoustic phonon spectra are calculated for semiconductor nanostructures. An irregular three-dimensional shape or realistic crystallographic symmetries allow only a numerical determination. Phonons are described within continuum linear elasticity theory as well as with atomistic models, which interaction parameters are determined by ab initio density functional calculations. Nanoparticles, especially when embedded in a different material, may be under substantial inhomogeneous stress. It is confirmed by atomistic calculations that their acoustic phonon modes can be described by modified inhomogeneous elastic constants going beyond linear elasticity. Implications for the dephasing of optical excitations in nanoparticles due to electron-acoustic phonon interaction are discussed.