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HL: Fachverband Halbleiterphysik

HL 15: Quantum Dots and Wires: Growth and Properties

HL 15.1: Vortrag

Dienstag, 18. März 2025, 09:30–09:45, H13

Predictive theory of multi-particle states of GaAs quantum dots — •Petr Klenovsky — Masaryk University, Brno, Czech Republic — Czech Metrology Institute, Brno, Czech Republic

The correlated multi-particle electronic structure of GaAs quantum dots (QDs) in AlGaAs matrix is studied. GaAs QDs have unique physical properties, like an absence of built in strain as well as exhibiting the effects of the weak confinement, leading to the superradiance. GaAs QDs are an almost ideal candidate as a source of single and entangled photons for usage in quantum cryptography and computing. Unfortunately, so far current physics models of their electronic structure were not successful to quantitatively reproduce observed experimental results like, e.g., binding energies of trions (X+ and X-) and biexciton (XX) with respect to exciton (X) as well as the radiative emission of those complexes. We endeavored to change that and show in this contribution the results of our improved theory model based on k·p approximation and configuration interaction (CI) schemes. Using that we demonstrate computed binding energies of X+, X-, and XX in agreement with experiment which are also converged with respect to the size of CI basis, i.e., they include the effects of the Coulomb correlation. While the latter is found to be of a paramount role, surprisingly, we also find that the binding energies strongly depend on the way the electron-electron and hole-hole exchange integrals are calculated. Our results show very good agreement with photoluminescence and nuclear spin relaxation experiments on GaAs/AlGaAs QDs.

Keywords: Biexciton; Configuration interaction; GaAs quantum dots; Correlated quantum theory