Metal-non-metal transition in heterostructures with thick spacer layers

Abstract

In the heterostructures with thick spacer layers the random potential in the channel created by remote impurity ions is smooth and can be treated classically, so that the percolation interpretation of the metal-non-metal transition (MNMT) is possible. The critical electron density n c of the MNMT is found as a function of the spacer width and the ion density. It is shown that at the given ion density the behaviour of the conductivity near the MNMT depends mainly on the product ns, where n is the electron density, and s — the width of the spacer layer. This result is compared with the experimental data by Jiang et al.[10]. The connection between the critical density n c for the transition without magnetic field and the width of the plateaus of the integer quantum Hall effect (IQHE) in a strong enough magnetic field is established. The width of the plateau as a function of spacer thickness and magnetic field is discussed.