The authors have calculated electronic deformation potentials of Si, Ge and zinc-blende-like GeSi for both hydrostatic as well as uniaxial strain along the (001) direction. The calculations have been performed with the self-consistent relativistic linear muffin-tin orbital (LMTO) method, including spin-orbit coupling, and show that the uniaxial spin-dependent deformation potential b2=-(0.05+or-0.05) eV for both Si, Ge, and GeSi. The volume scaling parameters of the spin-orbit splittings Delta 0 and Delta 1, dln Delta 0,1/dlnV, were calculated to be approximately=-0.6 for all three materials investigated. The error in the E0 gap introduced by the use of the local-density approximation is corrected by the introduction of extra potentials included self-consistently in the calculation, thus leading to pressure coefficients of the direct and indirect gaps which compare well with experiments and other recent calculations.
 

Solid State Communications, 75 39-43, 1990.