Electron correlations and logarithmic singularities in density of states and conductivity of disordered two-dimensional systems

A simple method is developed for obtaining results from the interaction theory proposed by Altshuler and Aronov (1979). This method yields the logarithmic singularities in the density of states and the conductivity of disordered 2D metals, in agreement with the results of those authors. It produces also the T^-1/2 behaviour for a disordered long wire. The correlation between the interaction theory, the localisation theory and experiment is discussed. In particular, it is pointed out that, at zero temperature and for materials for which the inverse screening length is much less than the Fermi wavevector K_F, both theories yield the same conductivity. Both effects are probably present in inversion layers.