Enhancement of Electron Spin Relaxation Time in Thin SOI Films by Spin Injection Orientation and Uniaxial Stress

The electron spin properties of semiconductors are of immense interest for their potential in spin-driven applications. Silicon is a perfect material for spintronics due to a long spin lifetime. Understanding the peculiarities of the subband structure and details of spin propagation in thin silicon films in the presence of the spin-orbit interaction is under scrutiny. We have performed simulations to obtain the surface roughness limited, acoustic-and optical-phonon mediated spin relaxation time, when the film is under shear strain. The degeneracy between the non-equivalent valleys is lifted by strain, which in turn subdues the dominating inter-valley relaxation components and increases the spin lifetime. We also elaborate on the injection orientation sensitive spin relaxation model and predict that the spin relaxation time is maximum, when the spin is injected in-plane, relative to the (001) oriented silicon film.