Galvanomagnetic effect in AlGaAs/GaAs heterostructures grown by organometallic vapor phase epitaxy

Abstract

A new galvanomagnetic effect in AlGaAs/GaAs heterostructures is described. The Hall coefficient of such structures is shown to decrease with the magnetic field in a low field regime where magnetoresistive effects are negligible. The effect is explained in terms of two-band conduction in the AlGaAs and in the two-dimensional electron gas at the heterojunction where the electrons have different energies and substantially differing mobilities and concentrations. It is shown that the low magnetic field Hall mobilities can be used to estimate the mobility of the two-dimensional electron gas in a heterostructure where there is parallel conduction.