Quantum hall effect in a two-dimensional electron-hole gas

We have shown experimentally that in a two-dimensional gas with coexisting electrons and holes the quantum Hall effect is determined by the degree of uncompensation of the system. A classical analysis of low-field magnetotransport measurements in GaSb-InAs-GaSb heterostructures gives individual carrier concentrations and mobilities for both electrons and holes. In the quantum Hall regime, with the Fermi level between electron and hole magnetic levels, the filling factor is the difference between the electron and hole filling factors. Similarly, the carrier density is the difference between the electron and hole densities, in analogy with the infinite-field limit of the classical Hall effect.