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 b allistic channels in parallel on a GaAs-AlGaAs heterostructure. Indepe ndent control over all the gates allows unprecedented flexibility to a djust both the size of the dot and the widths of the channels. In a pe rpendicular magnetic field we can obtain extremely large Aharonov-Bohm oscillations and a double-frequency oscillation indicative of edge st ate charging in an open system. At low magnetic fields we see no evide nce for any interaction between the one-dimensional subbands in the tw o channels.