Electron transmission and phase time in semiconductor superlattices

We discuss the time spent by an electron propagating through a finite periodic system such as a semiconductor superlattice. The relation between dwell-time and phase-time is outlined. The envelopes of phase-time at maximum and minimum transmission are derived, and it is shown that the peaks and valleys of phase-time are well described by parameters fitted at the extrema. For a many-period system this covers most of the allowed band.PACS Nos.: 03.65.Xp, 73.63.–b, 05.60.Cg