Selective population and detection of edge channels in the fractional quantum Hall regime

Transport in the fractional-quantum-Hall-effect (FQHE) regime is studied in a two-dimensional electron gas (2DEG) employing adjustable barriers as current and voltage probes. We find a fractionally quantized Hall conductance for integer filling factor in the bulk of 2DEG, as a consequence of the fractional filling factor in the probes. We argue that this effect is the first manifestation of adiabatic transport in the FQHE. The results are in agreement with a proposed Landauer-Büttiker formula in which each fractional edge channel contributes a conductance (1/3$e^2$/h.