AHARONOV-BOHM EFFECT AND ONE-DIMENSIONAL BALLISTIC TRANSPORT THROUGH 2 INDEPENDENT PARALLEL CHANNELS

We have developed a new technique to contact a submicrometer metal dot gate independently of surrounding gates. With this we have made two ballistic channels in parallel on a GaAs-AlGaAs heterostructure. Independent control over all the gates allows unprecedented flexibility to adjust both the size of the dot and the widths of the channels. In a perpendicular magnetic field we can obtain extremely large Aharonov-Bohm oscillations and a double-frequency oscillation indicative of edge state charging in an open system. At low magnetic fields we see no evidence for any interaction between the one-dimensional subbands in the two channels.