NATURE OF THE ELECTRONIC STATES IN A CHAIN OF POTENTIAL WELLS IN PRESENCE OF AN ELECTRIC-FIELD

A Kronig-Penney model with a constant electric field is used to study the transmission properties of a non-interacting electron one-dimensio nal(1D) ordered and disordered systems with uniformly distributed nega tive strengths of delta-function potentials (wells). In ordered system s we examine the origin of the jumps of the transmission coefficient a nd the short-range localization (occurring before the first jump) obse rved previously. For disordered wells, we also examine the phase-diagr am in the energy-disorder plane. The short-range localization is obser ved as a peak in the inverse participation ratio and as a minimum in t he localization length. We found that the two distinctive behaviours c orrespond to a negative differential resistance and to a resonance at particular points corresponding to the edges of the Brillouin zones. F urther discussions of these behaviours are included.