Contributions to Localization in the Silicon Inversion Layer from States in the Gap inSiOx

Abstract
Recent experiments on silicon inversion layers in the activated conductivity regime have shown a variety of electronic behaviors which are in marked disagreement with the predictions of Mott-Anderson localization, which is due to random static-potential fluctuations. It is argued here that there is an additional mechanism causing electron localization which involves electron-pair states in the energy gap of the disordered oxide. It is shown that by including this mechanism it is possible to account for a variety of these electronic properties including the dependence of the mobility edge on electron density.