Theory of finite-temperature screening in a disordered two-dimensional electron gas

A finite-temperature theory for the static screening of charged-impurity scattering in an electron layer is developed. The finite-temperature wave-vector-dependent electronic polarizability function is calculated including the effect of collisional broadening within a leading-order ladder-bubble diagrammatic expansion. At low temperatures such that kBT is smaller than the collisional level broadening, screening becomes independent of temperature. Implications of the theory for Ohmic transport in two-dimensional semiconductor systems (e.g., silicon inversion layer, modulation doped Alₓ{Ga}_{1{{-}}x}$As?(hyGaAs heterostructure) are discussed.