Exciton levels and fine-structure splitting in laterally-coupled quantum dot molecules are studied. The electron and hole tunneling energies as well as the direct Coulomb interaction are essential for the exciton levels. It is found that fine-structure splitting of the two-lowest exciton levels is contributed from the intra- and inter-dot exchange interactions, both of which are largely influenced by the symmetry and tunnel-coupling between the two dots. As the inter-dot separation is reduced, fine-structure splitting of the exciton ground state is largely increased while those of the excited states are decreased. Moreover, the dependence of the fine-structure splitting in quantum dot molecules on the Coulomb correlation is clearly clarified.
@article{arxiv.0705.3880,
title = {Fine-structure splitting of exciton states in quantum dot molecules: symmetry and tunnel-coupling effects},
author = {Dong Xu and Nan Zhao and Jia-Lin Zhu},
journal= {arXiv preprint arXiv:0705.3880},
year = {2015}
}