Abstract
This thesis is devoted to studying spin relaxations in two-dimensional electron gas (2DEG) confined at the interface of III-V semiconductor heterostructure. We demonstrate how to extend the semiclassical spin operator approach from systems governed by Rashba Spin-Orbit Interaction (SOI) to those governed by Dresselhaus SOI. A significant contribution of this thesis is successfully deriving the spin operator for Dresselhaus SOI in semiclassical path integral formalism. This achievement allows all previous results on Rashba SOI to be extended to Dresselhaus SOI. For instance, we introduce a special type of spin-field-effect-transistor which bases on both Rashba SOI andDresselhaus SOI. Additionally, we find the mechanism why some specific initial spin configurations in 2DEG channels will result in long relaxation times, as proposed by Mal'shukov. In that work they claimed that in diffusive regime, the relaxation rates of certain spin configurations are much slower than general configurations and should be proportional to square of d, where d is the width of the channel. Besides, we may also predict spin relaxations in ballistic regime, which is beyond the regions of Mal'shukov's study. In the end of our simulation, we found a work of Pershin in 2005 discussing long relaxation times in 2DEG channels. Apparently, he also found the same reason of relaxation slowdown as we did. Except for the theoretical work mentioned above, recently Awschalom also obtained the experimental results of slowdown of spin relaxation in 2DEG channels. Finally, a brief summary and an outlook to the future work are given.