Stability of negative and positive trions in quantum wires

TL;DR

This paper investigates the stability of negative and positive trions in quantum wires under strong confinement, revealing how particle localization and magnetic fields influence their binding energies and spectral lines.

Contribution

It introduces a numerical exactly solvable model to analyze trion stability considering electron and hole localization effects and magnetic field influences.

Findings

Equal electron and hole confinement favors $X^+$ stability.

Small localization imbalances can invert trion stability.

Magnetic fields can cause crossing of $X^+$ and $X^-$ photoluminescent lines.

Abstract

Binding energies of negative ($X^-$) and positive trions ($X^+$) in quantum wires are studied for strong quantum confinement of carriers which results in a numerical exactly solvable model. The relative electron and hole localization has a strong effect on the stability of trions. For equal hole and electron confinement, $X^+$ is more stable but a small imbalance of the particle localization towards a stronger hole localization e.g. due to its larger effective mass, leads to the interchange of $X^-$ and $X^+$ recombination lines in the photoluminescent spectrum as was recently observed experimentally. In case of larger $X^-$ stability, a magnetic field oriented parallel to the wire axis leads to a stronger increase of the $X^+$ binding energy resulting in a crossing of the $X^+$ and $X^-$ lines.