Tunneling conductivity oscillations in a magnetic field in metal-insulator-narrow-gap-HgCdTe structures: The energy spectrum and spin-orbit splitting of 2D states

Abstract

We study tunneling conductivity oscillations in a magnetic field in narrow-gap p-HgCdTe-oxide-metal (Yb, Al) structures. In tunnel structures with Yb we detect two types of tunneling conductivity oscillations. The first is related to the crossing of the Landau levels of two-dimensional (2D) states localized in the surface quantum well of the semiconductor, and has an energy EF+eV, where EF is the Fermi energy of the semiconductor and V is the bias voltage; the second has an energy EF. We find that in such structures with an asymmetric quantum well there is strong spin-orbit splitting in the spectrum of the 2D states. In p-HgCdTe-oxide-Al tunnel structures the surface potential is much weaker and only oscillations of the first type are observed. We find that in such structures there is only one spin state of the 2D carriers, while the second is pushed into the continuous spectrum because of strong spin-orbit coupling. To analyze the experimental results we calculate the spectrum of 2D states localized in the surface quantum well in a semiconductor with a Kane dispersion law. We find that all the experimental results are in good agreement with the results of calculations. Finally, we discuss the features of “kinematically coupled” states in an asymmetric quantum well.