Atomistic theory of dark excitons in self-assembled quantum dots of reduced symmetry

Abstract

We use an atomistic model to consider the effect of shape symmetry breaking on the optical properties of self-assembled InAs/GaAs quantum dots. In particular, we investigate the energy level structure and optical activity of the lowest energy excitons in these nanostructures. We compare between quantum dots with two-fold rotational and two reflections (C2v) symmetry and quantum dots in which this symmetry was reduced to one reflection only (Cs) by introducing a facet between the quantum dots and the host material. We show that the symmetry reduction mostly affects the optical activity of the dark exciton. While in symmetric quantum dots, one of the dark exciton eigenstates has a small dipole moment polarized along the symmetry axis (growth direction) of the quantum dot, in non-symmetric ones, the two dark excitons' dipole moments are predominantly cross-linearly polarized perpendicular to the growth direction and reveal pronounced polarization anisotropy. Our model calculations agree quantitatively with recently obtained experimental data.

References in corpus (6)

• Entangled Photon Pairs from Semiconductor Quantum Dots
• Improved fidelity of triggered entangled photons from single quantum dots
• Fast optical preparation, control and read-out of single quantum dot spin
• Determinisitic Writing and Control of the Dark Exciton Spin using Short Single Optical Pulses
• Polarization sensitive spectroscopy of charged Quantum Dots
• In-plane radiative recombination channel of a dark exciton in self-assembled quantum dots

Cited by in corpus (5)

• Exciton lifetime and emission polarization dispersion in strongly in-plane asymmetric nanostructures
• Probing the dark exciton states of a single quantum dot using photocurrent spectroscopy in magnetic fields
• Resonant optical control of the spin of a single Cr atom in a quantum dot
• The optical Stark shift to control the dark exciton occupation of a quantum dot in a tilted magnetic field
• Optical control of an individual Cr spin in a semiconductor quantum dot