Quantum Hall effect in devices with an inner boundary

The authors have produced window-shaped quantum Hall effect samples with contacts both on the inner and on the outer edges. This allowed the study of potentials appearing on contacts inside a sample but still lying on an edge and hence not decoupling from the two-dimensional electron gas. The experimental results indicate that under quantum Hall effect conditions there is no electron transfer between the inner and the outer edge. Hall voltages appear only when the potential probes are on the same edge as the current contacts.