Potential screening in the integer quantum Hall effect: evidence for bulk currents

The current distribution in the integer quantum Hall regime was studied by inductive coupling technique and transport measurements. Using an inductive coupling method we were able to study the screening properties of a two-dimensional electron gas (2DEG). We found that having gates in the vicinity of the 2DEG influence the distribution of the non-equilibrium Hall current injected into the sample. From the inductive measurements we proved that the non-equilibrium Hall current is carried by bulk states. We also demonstrated the role of externally applied electric fields. 2DEG V-grooved samples allowed us to realize a configuration at which the normal component of the magnetic field to the plane of the 2DEG alternates in sign. We showed that for such a magnetic field configuration, the quantum Hall effect survives although the magnitude of the quantized Hall coefficient is multiplied by the number of the grooves. This observation can easily be explained by the alternation of the current direction in each subsequent sidewall of the groove, and therefore implies the current flow in the bulk of the sample.