Determination of the resistance across incompressible strips through imaging of charge motion

Using charge-accumulation imaging, we measure the charge flow across an incompressible strip and follow its evolution with magnetic field. The strip runs parallel to the edge of a gate deposited on the sample and forms at positions where an exact number of integer Landau levels is filled. An $\mathrm{RC}$ model of charging fits the data well and enables us to determine the resistance across the strip. Surprisingly, we find that the strip becomes more resistive as its width decreases.