  Persistent current is a small but perpetual electric current that flows in
metallic rings in the absence of any applied source. We compute the persistent
currents of one-dimensional disordered metallic rings of interacting electrons
in the presence of impurity on lattices up to 8-sites at half-filling and also
away from half-filling using the Lanczos algorithm. For the case of
half-filling, we observe that both interaction and disorder suppress the
amplitude of the persistent currents by localizing the electrons. However, in
the presence of disorder and away from half-filling, the Coulomb interaction is
observed to enhance the persistent current. Furthermore, in the half-filled
case, there is a transition from metal to insulator as U is increased
significantly. In addition, shifting away from half-filling, the system is
observed to remain in the metallic state irrespective of the value of the
Coulomb repulsion (U). The observations are quite in agreement with the results
from other techniques.
