Metal-insulator transition induced by fluctuations of the magnetic potential in the quantum well of the semiconductor structure with magnetic impurities' δ-layer

We consider the metal-insulator transition occurring at lowering temperature in the two-dimensional channel of semiconductor heterostructures with delta-layer of magnetic impurities. In contrast to the similar transition produced by the localization of charge carriers in the fluctuating electric potential, the investigated transition is associated with the fluctuating magnetic potential generated by the impurity magnetization. With lowering temperature, the magnetic potential grows and the system is decomposed into areas with strongly differing local carrier concentrations. The current flow (in the resultant composite medium) is obstructed by Coulomb blockade and occurs via the thermal activation. It is just the metal-insulator transition. (C) 2011 Elsevier B.V. All rights reserved.