Parallel magnetoconductance of interacting electrons in a two-dimensional disordered system

The transport properties of interacting electrons for which the spin degree of freedom is taken into account are numerically studied for small two-dimensional clusters for which the localization length is larger than the system size. On-site electron-electron interactions tend to delocalize the electrons, while long-range interactions enhance localization. On careful examination of the transport properties, we reach the conclusion that it does not show a two-dimensional metal-insulator transition driven by interactions. A parallel magnetic field leads to enhanced resistivity, which saturates once the electrons become fully spin polarized. The strength of the magnetic field for which the resistivity saturates decreases as the electron density goes down. Thus, the numerical calculations capture some of the features seen in recent experimental measurements of parallel magnetoconductance.