THZ-FIELD INDUCED NONLINEAR TRANSPORT AND DC VOLTAGE GENERATION IN A SEMICONDUCTOR SUPERLATTICE DUE TO BLOCH OSCILLATIONS

We report on a theoretical analysis of terahertz (THz-) field induced nonlinear dynamics of electrons in a semiconductor superlattice that are capable to perform Bloch oscillations. Our results suggest that for a strong THz-fieId a de voltage should be generated. We have g e analyzed the real-time dynamics using a balance equation approach to describe the electron transport in a superlattice miniband. Taking account of both Bloch oscillations of electrons in a superlattice miniband and dissipation, we studied the influence of a strong THz-field on currently available superlattices at room temperature. We found that a THz-field can lead to a negative conductance resulting in turn in a THz-field induced de voltage, and that the voltage per superlattice period should show, for varying amplitue of the THz-field, a form of twisted plateaus with the middle points being with high precision equal to the photon energy divided by the electron charge. We show that the THz-field can cause fast switching from the zero-voltage to the finite voltage state, and that in the finite voltage state dynamic localization of the electrons in a miniband occurs.