We present photoluminescence studies of CdTe and CdMnTe quantum dots grown in two adjacent layers. We show that when the dots are 8 nm apart, their magnetooptical properties - Zeeman shifts and transition linewidths - are analogous to those of individual CdTe or CdMnTe dots. When the dots are grown closer, at a distance of 4 nm, it becomes possible to tune the electron states to resonance and obtain a formation of a molecular state hybridized over the two dots. As a result of the resonant enhancement of the electron-Mn ion exchange interaction, spectroscopic signatures specific to spin-dependent inter-dot coupling appear. Namely, an anomalous increase of the Zeeman shift and a resonant increase in the transition linewidth are observed. A simple model calculation allows us to quantitatively reproduce the experimental results.
@article{arxiv.1502.03589,
title = {Optical signatures of spin dependent coupling in semimagnetic quantum dot molecules},
author = {Ł. Kłopotowski and P. Wojnar and Ł. Cywiński and T. Jakubczyk and M. Goryca and K. Fronc and T. Wojtowicz and G. Karczewski},
journal= {arXiv preprint arXiv:1502.03589},
year = {2015}
}