  The metal-insulator transition (MIT) observed in two-dimensional (2D) systems
is apparently contradictory to the well known scaling theory of localization.
By investigating the conductance of disordered one-dimensional systems with a
finite phase coherence length, we show that by changing the phase coherence
length or the localization length, it is possible to observe the transition
from insulator-like behavior to metal-like behavior, and the transition is a
crossover between the quantum and classical regimes. The resemblance between
our calculated results and the experimental findings of 2D MIT suggests that
the observed metallic phase could be the result of a finite dephasing rate.
