ELECTRIC-FIELD EFFECT ON THE TRANSMITTIVITY OF APERIODIC KRONIG-PENNEY CRYSTALS

We describe the effect of a static and uniform electric field on the e lectronic transport properties of one-dimensional periodic and determi nistic aperiodic systems described by the Kronig-Penney model. We stud y the crystal transmittivity as a function of the length of the sample and of the field strength. In the periodic case we interpret the resu lts exploiting the tilted band scheme and point out regions with a mor e than exponential decreasing rate of transmittivity. In the case of a n incommensurate slowly varying potential we interpret the fine struct ure of the transmittivity by means-of a continuous approximation. In t he pseudorandom case we confirm the delocalization effect of the field and we compare the results with the purely random case.