Transport in GaAs/AlxGa1-xAs superlattices with narrow minibands: Effects of interminiband tunneling

The results of experimental investigations for the I-V characteristics are presented for superlattices based on GaAs/AlxGa1-xAs with thin barriers in the electric-field region with an intense interminiband tunneling. The regular features for the I-V characteristics are found in the voltage range adequate to the static positive differential conductivity in the superlattice. On the basis of calculations for the Wannier-Stark levels, it is established that the observed features are associated with the resonant tunneling between these levels belonging to quantum wells located at a distance from 6-13 superlattice periods from each other. It is noted that the similar resonant delocalization of Wannier-Stark wave functions can lead to the existence of dynamic negative differential conductivity for the laser type of an appreciable value in such superlattices.