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HL: Fachverband Halbleiterphysik

HL 42: Optical Properties of Quantum dots: Theory and Simulation

HL 42.4: Vortrag

Donnerstag, 28. Februar 2008, 10:15–10:30, EW 201

Atomistic Theory of Excitonic Effects in Nanostructures — •Gabriel Bester — Max Planck Institute for Solid State Research, Stuttgart, Germany

The confinement in all three space dimensions given in nanostructures leads to several new phenomena of fundamental interest that can be handled by different levels of theory. For nanostructures of small size, the atomistic nature and ensuing symmetry is most relevant and the system should be viewed as a large assembly of atoms. The adequate description is then atomistic in nature, such as in tight binding or pseudopotential approaches. For larger structures, the atomistic nature tends to become less important while particle-particle correlations become more relevant. In this size regime descriptions such as effective mass in the single band or in the multiband approach (k.p) followed by configuration interaction have established themselves. I will present a theoretical framework, based on empirical pseudoptentials and configuration interaction calculations that enables us to address the intermediate length scale where both, the atomistic nature and correlations are retained. I will illustrate the method by showing recent applications in the realm of quantum dot physics where properties such as quantum entanglement [1], piezoelectricity [2] or Coulomb blockade [3] have been investigated.

[1] Bester et al., Phys. Rev. Lett. 93 047401 (2004). [2] Bester et al. Phys. Rev. Lett. 96, 187602 (2006). [3] Ediger, Bester, et al., Nature Physics 3, 774 - 779 (2007).