Observation of wave packet revivals in semiconductor superlattices

Summary form only given. There was a longstanding theoretical debate whether Bloch-oscillations or their energy-domain equivalent, Wannier-Stark-states, exist or whether they are suppressed by Zener-tunneling to higher bands. Both phenomena have recently been observed in many experiments in semiconductor heterostructures where coherence of the electronic ensemble was preserved longer than the Bloch-oscillation period. Surprisingly, the effect of Zener tunneling was never observed or discussed in these publications. To investigate this effect, we have designed a shallow, 35 period, 50/54 /spl Aring/ GaAs/Al/sub 0.11/Ga/sub 0.89/As superlattice whose wells contain only one below barrier electronic miniband.