BALLISTIC TRANSPORT IN ELECTRON STUB TUNERS - SHAPE AND TEMPERATURE-DEPENDENCE, TUNING OF THE CONDUCTANCE OUTPUT, AND RESONANT-TUNNELING

Electron stub tuners (EST's) are devices which yield a periodic conductance G(c) as a function of the stub length c. The ballistic conductance in EST's is studied as a function of temperature and stub shape. We find that the smearing effects of finite temperature are dependent upon c. The stub shape does not affect the qualitative behavior of G(c), but does affect the period. The width of the minima in G(c) can be tuned by using EST superlattices or double EST's to achieve a square wave output with possible application in analog-to-digital converters. We also show how a periodic G(c) can be obtained in the multimode case. Finally, we show how it is possible to replace the conductance minima in G(c) (corresponding to resonant reflection) with peaks that result from resonant tunneling, by allowing coupling to higher order quantum wire modes.