Experimental determination of the current flow in the quantum Hall regime

We have developed a new method of determining the interior potential distribution, and hence the current flow, in a quantized two-dimensional electron gas (2DEG) at low temperature and high magnetic fields. Our results show that current carrying states exist in the bulk of the 2DEG and that the distribution of current changes with source-drain current and can vary appreciably over a small range of magnetic field well within the quantum Hall regime. In addition, increasing σxx reduces the variation in the current distribution with magnetic field. © 1986.