Adjusting the coherent transport in finite periodic superlattices

The coherent transmission function and the tunneling time of one-dimensional arbitrary finite periodic structures are adjusted without changing the resonance energies and therefore the band positions. The method is based on modifications of the single period which are reflected in a similarity transformation of the corresponding transfer matrix. Applied to semiconductor superlattices a strong tuneable increase of the average miniband transmission is obtained. The maximum of the average miniband transmission is reached if the single period is built by a double barrier resonant tunneling diode. The fundamentally different transmission behavior compared to a standard superlattice is analyzed. Calculations of the phase tunneling time show that the increase of the transmission comes along with a faster tunneling process through the transmission resonances. All results are valid for any number of periods.