The temperature dependence of electron spin coherence in singly negatively charged (In,Ga)As/GaAs quantum dots is studied by time-resolved Faraday rotation. The decoherence time T2 is constant on a microsecond scale for temperatures below 20 K, for higher temperatures it shows a surprisingly sharp drop into the nanoseconds range. The decrease cannot be explained through inelastic scattering with phonons, and may be related with elastic scattering due to phonon-mediated fluctuations of the hyperfine interaction.
@article{arxiv.0803.1579,
title = {Temperature induced spin coherence dissipation in quantum dots},
author = {F. G. G. Hernandez and A. Greilich and F. Brito and M. Wiemann and D. R. Yakovlev and D. Reuter and A. D. Wieck and M. Bayer},
journal= {arXiv preprint arXiv:0803.1579},
year = {2008}
}