Strongly confined 2D parabolic quantum dot: Biexciton or Quadron?

TL;DR

This theoretical study investigates how strong lateral confinement in 2D parabolic quantum dots influences the formation of complex excitonic states, revealing conditions favoring quadron over biexciton formation.

Contribution

It introduces a theoretical analysis of quadron formation in strongly confined 2D quantum dots, highlighting the role of confinement in excitonic complex stability.

Findings

Quadron has positive binding energy under strong confinement.

Biexciton has negative binding energy in the same conditions.

Strong confinement favors quadron formation over biexciton.

Abstract

Excitonic systems localized in a single InAs/GaAs parabolic quantum dot are studied theoretically using an unrestricted Hartree-Fock method. The binding energies of excitons, conventional biexcitons and quadrons - four particles system of two electrons and two holes, in the ground state have been obtained as functions of magnetic field and confinement potential. It is found that for strong confinement, while the binding energy of biexciton is negative, the binding energy of quadron is positive, suggesting the strong lateral confinement of the parabolic quantum dot supports the formation of a quadron rather than a biexciton.