Non-linear exciton spin-splitting in single InAs/GaAs self-assembled quantum structures in ultrahigh magnetic fields

TL;DR

This study investigates how magnetic fields influence exciton spin-splitting and diamagnetic shifts in single InAs/GaAs quantum structures, revealing non-linear behaviors linked to light hole contributions at high fields.

Contribution

It demonstrates non-linear exciton spin-splitting in quantum dots under ultrahigh magnetic fields, highlighting the role of geometric confinement and valence band mixing.

Findings

Non-linear spin-splitting observed at high magnetic fields.

Deviations from simple field dependence in weakly confined dots.

Light hole admixture influences exciton properties at high fields.

Abstract

We report on the magnetic field dispersion of the exciton spin-splitting and diamagnetic shift in single InAs/GaAs quantum dots (QDs) and dot molecules (QDMs) up to $B$ = 28 T. Only for systems with strong geometric confinement, the dispersions can be well described by simple field dependencies, while for dots with weaker confinement considerable deviations are observed: most importantly, in the high field limit the spin-splitting shows a non-linear dependence on $B$, clearly indicating light hole admixtures to the valence band ground state.