Magnetotransport in a pseudomorphic GaAs/GaInAs/GaAlAs heterostructure with a Si delta-doping layer

TL;DR

This study investigates the magnetotransport properties of a pseudomorphic GaAs/GaInAs/GaAlAs heterostructure with a Si delta-doping layer under high magnetic fields, revealing effects like magnetic freeze-out and quantization in electron gases.

Contribution

It provides new insights into the effects of Si delta-doping on magnetotransport in GaAs-based heterostructures at high magnetic fields, supported by both experimental data and theoretical modeling.

Findings

Magnetic freeze-out occurs at low electron densities in the delta-layer.

High electron densities lead to quantization of electron motion in both quantum well and delta-layer.

Experimental results agree well with the theoretical model.

Abstract

Magnetotransport properties of a pseudomorphic GaAs/Ga0.8In0.2As/Ga0.75Al0.25As heterostructure are investigated in pulsed magnetic fields up to 50 T and at temperatures of T=1.4 K and 4.2 K. The structure studied consists of a Si delta-layer parallel to a Ga0.8In0.2As quantum well (QW). The dark electron density of the structure is n_e=1.67x 10^16 m^-2. By illumination the density can be increased up to a factor of 4; this way the second subband in the Ga0.8In0.2As QW can become populated as well as the Si delta-layer. The presence of electrons in the delta-layer results in drastic changes in the transport data, especially at magnetic fields beyond 30 T. The phenomena observed are interpreted as: 1) magnetic freeze-out of carriers in the delta-layer when a low density of electrons is present in the delta-layer, and 2) quantization of the electron motion in the two dimensional electron gases in both the Ga0.8In0.2As QW and the Si delta-layer in the case of high densities. These conclusions are corroborated by the numerical results of our theoretical model. We obtain a satisfactory agreement between model and experiment.