Intersubband spin relaxation reduction and spin lifetime enhancement by strain in SOI structures

Electron spin attracts much attention as an alternative to the electron charge degree of freedom for low-power reprogrammable logic and non-volatile memory applications. Silicon appears to be the perfect material for spin-driven applications. An order of magnitude enhancement of the electron spin lifetime in (0 0 1) silicon thin films by shear strain is shown. It is demonstrated that spin-flip scattering processes between the two [0 0 1] valleys are responsible for spin relaxation in thin (0 0 1) silicon films. The enhancement of the spin lifetime is the result of the suppression of inter-valley scattering caused by the shear strain induced equivalent [0 0 1] valley splitting.