| Popis: |
Within a single-band tight-binding model, we investigate the dynamics of a one-dimensional semiconductor superlattice with an impurity driven by a dc-ac electric field. By numerically calculating the quasienergy spectrum and the probability propagators, we find that the dynamic localization condition is not destroyed by the impurity, but the local dynamics of the system is sensitively dependent on the relation of the impurity potential, the Bloch oscillation frequency and the ac field frequency. In appropriate circumstances, the dynamics of the system is dominated by resonant oscillations between the impurity and it nearest-neighbor sites. Such an effect might find important application for generating electromagnetic radiation and systematic study of localization phenomena. (C) 2002 Published by Elsevier Science B.V. |
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