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The peculiarity of planar quantum magnetotransport in the type II broken-gap p-GaInAsSb/p-InAs heterostructures at high magnetic fields has been investigated. The structure of the hybridized energy spectrum of a two-dimensional semimetal channel at a single type II broken-gap heterointerface was considered in dependence on the composition of the quaternary solid solution. A transition from a conducting state to a dielectric state (quantum insulator) for a 2D-semimetal channel at the heteroboundary was observed in quantizing magnetic fields under the condition of simultaneous filling of the first Landau levels for 2D-electron and interface hole states. [ABSTRACT FROM AUTHOR]

The authors studied the features of planar and vertical quantum magnetotransport in the broken-gap type II p-GaInAsSb/p-InAs heterostructure. This study reveals the structure of the hybridized energy spectrum of a two-dimensional semi-metallic channel at a single broken-gap type II heterointerface. It is demonstrated that an energy diagram of Landau levels can be visualized for a hybridized electron-hole system taking into account their spin splitting and mutual intersections. [ABSTRACT FROM AUTHOR]

The formation of self-consistent quantum wells for electrons and holes in a P(N)-GaInAsSb/p-InAs broken-gap type II heterojunction with an abrupt planar interface (a transition layer of the order of 1.2 nm thick) upon variation of the type and level of doping of the semiconductors in contact is controlled by the overlap of the energy bands at the heterointerface. In a study of the vertical magnetotransport through a GaInAsSb/p-InAs broken-gap type II heterointerface it is shown that the increase of the localization of the two-dimensional electrons in the electron channel at the interface leads to the formation of a “soft” Coulomb gap in the tunneling density of states. In magnetic fields below 15 T at helium temperature a transition from the state with a “soft” Coulomb gap to an insulator state (a hard energy gap at a conductance value of σtun∼10-8 Ω-1) is observed under the condition that the Fermi level for the two-dimensional electrons lies in the interval between the lowest Landau levels for the ν=2 plateau on the ρxy curve. As the external bias across the heterojunction is increased, the threshold offset from the insulator state is due to one-electron tunneling between individual closed regions of extended electronic states of the Landau level closest to the Fermi level. [ABSTRACT FROM AUTHOR]