Spin Dynamics of n-doped Gallium Arsenide

The emerging technology of spintronics promises to revolutionise computing by allowing considerably more energy
efficient computing than is currently possible. Gallium Arsenide is one candidate material for use in semiconductor spintronic devices
and as such detailed study of the spintronic properties of Gallium Arsenide is required. In this thesis we develop a
semiclassical approach to the simulation of the electron population in Gallium Arsenide. We then use this model to look at the properties of the electron system, in particular the
time taken for the electron population to undergo spin depolarisation.
Comparison of the results to experimental values for the spin depolarisation suggest that the currently well accepted approach is accurate for low to moderate n type doping densities, but for higher densities there
is a significant departure from the experimentally obtained results. We explore a number of improvements to the usual model showing substantial improvement in the range of densities that
can be accurately predicted.

As Dilute Magnetic Semiconductors have been the topic of substantial research, we also apply the model to investigate the properties of an magnetic impurity in n doped Gallium Arsenide.
We compare the results to the Langevin enhanced Landau Lifshitz Gilbert equation, which shows good agreement allowing us to predict an appropriate damping constant as a result of the magnetic
interaction with the electron population. We also investigate the nature of the noise felt by the magnetic atom showing that the usual white noise approximation is of limited validity.