Width of compressible strips in quantum Hall regime

We have investigated the width of the compressible strips in the edge state by magnetocapacitance between two-dimensional electron gas and a metal gate. The detail of Landau level filling factor dependence of the width is measured around the quantum Hall plateaux, and the influence of confinement potential on the width has been studied by tuning the side gate voltage. It is confirmed that the width is mainly governed by the depletion region at the sample boundary; the spatially gentle confinement potential forms wider compressible and incompressible strips. The nonlocal resistance has been also studied in the samples with tunable confinement potential by side gate, which supports the result of the capacitance measurement.