Following the introduction and motivation described above, the concrete structure of the thesis is outlined as follows.
Chapter 4 provides an introduction to the band structure calculations. Principles of the cellular and the variational methods are described. Then the k⋅p method and the mechanisms of the spin relaxation in semiconductors are presented.
Chapter 5 starts from the two-band k⋅p Hamiltonian with shear strain and spin properly included. The presented Hamiltonian is then rotated and a semi-analytical wave function calculation procedure is shown. The analytical solution is compared against numerically calculated results. The wave functions and the valley splitting is then investigated for different film thicknesses, values of the in-plane wave vector, and shear strain.
Chapter 6 presents a surface roughness matrix elements calculation procedure and investigates intrasubband and intersubband matrix elements. Then the model for momentum relaxation time for surface roughness limited and phonon induced momentum scattering rates is described. Afterwards the results for mobility and momentum relaxation time are provided.
Chapter 7 starts from the surface roughness limited spin relaxation matrix elements calculation and the origin of hot spots are disclosed. Then spin lifetime due to intravalley, intervalley scattering between equivalent and non-equivalent valleys, and surface roughness spin relaxation is calculated. The inclusion of zero-strain valley splitting is performed by considering the valley coupling through the Γ-point.
Chapter 8 shows the three-layer Datta-Das spin field effect transistor (SpinFET) model and presents the results of tunneling magnetoresistance oscillations for the SpinFET with silicon and InAs channels.