Quantum Transport in Electron Waveguides: New Knobs to Play With

Rings fabricated from one dimensional GaAs heterostructures display a suppression of the Aharonov-Bohm effect at magnetic fields of about .75-1.0 Tesla. This is in contrast to metal rings where the effect persists to the highest fields used so far. We discuss experiments performed on electron waveguide rings connected to 4 leads, employing IV-curve and second harmonic generation techniques. The implications for several models of the quenching of the Aharonov-Bohm Effect will be mentioned. Preliminary results on rings with gates on one branch will also be presented.