Electron-electron interactions in highly disordered two-dimensional systems

We investigate the use of three well established methods to model the electron-electron interaction correction to the conductivity in highly disordered two-dimensional systems. In order to determine the interaction correction delta sigma(ee), we use each method to fit experimental magnetoconductivity data from highly disordered Si:P delta-doped two-dimensional electron systems having conductivities ranging from k(F)l similar to 5 to 30. From this analysis we find that none of the three methods fits the data over the whole range of conductivities achievable. Consequently, we present a new method of extracting delta sigma(ee), based on the elimination of the interaction correction from the resistivity tensor, which is effective for extracting delta sigma(ee) over the complete range of conductivities studied. We find delta sigma(ee) between -5.5e(2)/pi h and -7.5e(2)/pi h at 0.5 K for our samples.