  We examine some nontrivial consequences that emerge from interpreting a
position-dependent mass (PDM) driven Duffing oscillator in the presence of a
quartic potential. The propagation dynamics is studied numerically and sensi-
tivity to the PDM-index is noted. Remarkable transitions from a limit cycle to
chaos through period doubling and from a chaotic to a regular motion through
intermediate periodic and chaotic routes are demonstrated.
