Forming and confining of dipolar excitons by quantizing magnetic fields

TL;DR

This paper demonstrates that perpendicular magnetic fields can effectively trap and confine dipolar excitons in quantum wells, significantly increasing their density and enabling detailed spectroscopic studies of hole densities.

Contribution

It introduces a method to efficiently trap and stabilize dipolar excitons using magnetic fields, achieving high exciton densities and tunable hole densities in quantum well structures.

Findings

Excitonic density increased to ~10^11 cm^-2.

Hole density tunable over an order of magnitude up to 2.5×10^11 cm^-2.

Magnetic fields enable effective exciton confinement and stabilization.

Abstract

We show that a magnetic field perpendicular to an AlGaAs/GaAs coupled quantum well efficiently traps dipolar excitons and leads to the stabilization of the excitonic formation and confinement in the illumination area. Hereby, the density of dipolar excitons is remarkably enhanced up to $\sim 10^{11} cm^{-2}$. By means of Landau level spectroscopy we study the density of excess holes in the illuminated region. Depending on the excitation power and the applied electric field, the hole density can be tuned over one order of magnitude up to $\sim 2.5$ $10^{11} cm^{-2}$ - a value comparable with typical carrier densities in modulation-doped structures.