2.5.4 Alloy Scattering

When an alloy of Si and Ge is considered, there is an additional scattering mechanism due to the atomic disorder. To describe this mechanism it is necessary to define the model of disorder and the scattering potential.

The model used in this work for the SiGe alloy is that of Harrison-Hauser [40], which uses Warren-Cowley's approach for the disorder model [41] and Mott's inner-potential model for the scattering potential. The resulting scattering rate is given by the following expression which takes both intravalley and intervalley scattering into account:

$$\lambda_\textrm{alloy}(\epsilon)=\frac{\pi}{\hbar}(1-x)x\Omega_\textrm{cell}U^{2}g(\epsilon),$$ (2.138)

where $x$ is the mole fraction of one of the materials, $\Omega_\textrm{cell}$ is the volume of the elementary cell, and $U$ is the alloy scattering potential. S. Smirnov: