Donor Centers and Absorption Spectra in Quantum Dots

TL;DR

This paper investigates how donor centers in quantum dots affect their electronic and optical properties under magnetic fields, revealing ground-state transitions observable in absorption spectra.

Contribution

It provides a detailed analysis of donor center effects on quantum dot spectra using exact diagonalization, highlighting the influence of ion position and magnetic field.

Findings

Ground-state transitions are induced by donor centers.

Transition magnetic field strength increases as ion approaches the confinement plane.

Absorption spectra clearly show these transitions.

Abstract

We have studied the electronic properties and optical absorption spectra of three different cases of donor centers, D^{0}, D^{-} and D^{2-}, which are subjected to a perpendicular magnetic field, using the exact diagonalization method. The energies of the lowest lying states are obtained as function of the applied magnetic field strength B and the distance zeta between the positive ion and the confinement xy-plane. Our calculations indicate that the positive ion induces transitions in the ground-state, which can be observed clearly in the absorption spectra, but as zeta goes to 0 the strength of the applied magnetic field needed for a transition to occur tends to infinity.