  We present a numerical study of electron transport in a thin film of varying
disorder strength with the distance from its surface. A simple tight-binding
model is used to describe the system, in which the film is attached to two
metallic electrodes and the coupling of this film to the electrodes is
illustrated by the Newns-Anderson chemisorption theory. Quite interestingly we
observe that, in the smoothly varying disordered film current amplitude
increases with the increase of disorder strength in the strong disorder regime,
while it decreases in the weak disorder regime. This behavior is completely
opposite from a conventional disordered film, where current amplitude always
decreases with the increase of disorder strength.

Mesoscale and Nanoscale Physics;Materials Science