Magnetoresistance of two-dimensional electrons in modulation-doped Cd1−xMnxTe/Cd1−yMgyTe SQWs: the variation with carrier concentration

The magneto-transport properties of two-dimensional electron gas (2DEG) of n-type modulation-doped Cd1−xMnxTe/Cd1−yMgyTe single quantum wells were investigated under magnetic fields up to View the MathML source applied perpendicular to the 2D plane at View the MathML source. The 2D carrier concentration was varied in the range of 1.8–View the MathML source. Apart from the quantum behavior in the magneto- and Hall resistance, a positive and successively negative magnetoresistance (MR) appeared at low magnetic fields. This effect was not observed in non-magnetic 2DEG. This peculiar MR is interpreted as caused by the enhanced spin-splitting in magnetic 2DEG. The appearance of the positive and negative MR was more distinct in a sample with lower carrier concentrations. The positive MR was analyzed on the basis of the theoretical model of the quantum correction to the conductivity in the disordered system.