FROZEN ELECTRON-SOLID IN THE PRESENCE OF SMALL CONCENTRATIONS OF DEFECTS

We investigate the freezing of a low-density electron liquid for a two -dimensional electron layer in the presence of low levels of defects t ypical of a high-quality semiconductor interface. We use a memory func tion approach with mode-coupling approximation and include the effect of strong electron-electron correlations, which we find are crucial fo r the transition. For a range of low impurity concentrations we find a stable frozen solid with a liquidlike short-range order. At higher im purity concentrations the electrons localize separately and there is n o short-range order. Our electron-density vs peak-mobility phase diagr am at zero temperature is in agreement with recent metal-insulator tra nsition experiments in silicon heterostructures.