Screening-theory-based description of the metallic behavior in Si/SiGe two-dimensional electron systems

Motivated by recent experimental work we calculate the temperature, density, and parallel magnetic field dependence of low temperature electronic resistivity in two-dimensional (2D) high-mobility $\mathrm{Si}∕\mathrm{Si}\mathrm{Ge}$ quantum structures, assuming the conductivity limiting mechanism to be carrier scattering by screened random charged Coulombic impurity centers. Our calculated temperature and field dependence is qualitatively similar to recent experimental observations in $\mathrm{Si}∕\mathrm{Si}\mathrm{Ge}$ 2D structures, where charged impurity scattering is known to be important. In particular, our theory correctly predicts the experimentally observed metallic temperature dependence of 2D resistivity in the fully spin-polarized system.