Spin-Orbit Interaction and Phonon-Mediated Spin Dynamics in Quantum Dots

Spin effects in III-V semiconductor quantum dot devices are being exploited in both ` classical' photonic devices (such as spin VCSELs and as an additional label in photonic communication systems) and in classical photonic devices. The modelling formalisms for the two regimes are often very different due to the high temperature (room temperature) regime of the former and the low temperature (milli-Kelvin) regime of the latter. In this talk we unite the two approaches into a simpler formalism and investigate the similarities. Model expressions for the spin-orbit interaction (SOI) in a quantum dot are obtained. The resulting form does not neglect cubic terms and allows for a generalized structural inversion asymmetry. We also obtain analytical expressions for the coupling between states for the electron-phonon interaction and use these to derive spinrelaxation rates, which are found to be qualitatively similar to those derived elsewhere in the literature. We find that, due to the inclusion of cubic terms, the Dresselhaus contribution to the ground state spin relaxation disappears for spherical dots. A comparison with previous theory and existing experimental results shows good agreement thereby presenting a clear analytical formalism for future developments. Comparative calculations for potential materials are presented.