Magnetoresistance study for systems of interacting electrons in two dimensions

The influence of Coulomb interaction and weak perpendicular magnetic field on the transport properties of spinless electrons in small disordered two dimensional systems is studied within a tight binding model. We trace the participation ratio of the renormalized zero-temperature tunneling amplitude as function of interaction strength U and magnetic field H, and find typical negative magnetoresistance for small disorder, while the behavior is more complicated for stronger disorder. The results suggest an effective weakening of the magnetic field for stronger Coulomb interaction in agreement with previous results for quantum dots.