Semimetal-Insulator Transition in Two-Dimensional System at the Type II Broken-Gap InAs/GalnAsSb Single Heterointerface

The magnetotransport properties of a two-dimensional (2D) electron-hole system localized on a single type II broken-gap heterointerface have been studied in a pulsed magnetic field up to 35 T. The step-like decrease of the driving current indicates a conductivity path through localized states of the 2D system. Up to ∼20 T, Hall resistance (Rxy) is completely antisymmetric, while, at the onset of the insulating state, Rxy switches its behavior to become totally symmetric which does not depend on the polarity of the applied magnetic filed. The insulating behavior is ascribed to the formation of energy mini-gaps in the 2D system spectrum due to the intersubband mixing at the type II broken-gap heterointerface and anticrossing of Landau levels of electrons and holes.