Uniaxial Shear Strain as a Mechanism to Increase Spin Lifetime in Thin Film of a SOI-Based Silicon Spin FETs

In this chapter we investigate spin relaxation in thin silicon films. We employ a k p based approach to investigate surface roughness and phonon induced momentum and spin relaxation matrix elements. We show that the spin relaxation matrix elements strongly decrease with shear strain increased. In order to meet computational requirements with actual resources needed for relaxation time calculations, we demonstrate a way to find the subband wave function from the k p model analytically. We consider the impact of the surface roughness and phonons on transport and spin characteristics in ultra-thin SOI MOSFET devices. We show that the regions in the momentum space responsible for strong spin relaxation can be efficiently removed by applying uniaxial shear strain. The spin lifetime in strained films can be improved by orders of magnitude.