Donor Electron Spin Relaxation in Silicon

A study of donor electron spin relaxation which can occur due to the presence of spin-orbit coupling is carried out. It is found that at helium temperatures both the direct and Raman processes are too weak to be observed, but that at 14^∘{}K the Raman process yields a relaxation time of 1 sec.Several mechanisms of relaxation due to the interaction with conduction electrons are also discussed. It is found that none of them can compete with the exchange-scattering process considered by Pines, Bardeen, and Slichter.