Two-dimensional states at the HgTe/Hg0.05Cd0.95Te interface as determined from the tunneling investigations.

Abstract

The results of tunneling investigations performed on HgTe/${\mathrm{Hg}}_{0.05}$${\mathrm{Cd}}_{0.95}$Te heterostructures grown by molecular-beam epitaxy are presented. Oscillations in the conductivity due to tunneling are observed as a function of magnetic field and bias voltage. It is shown that these oscillations are related to changes in the barrier transparency, which occur as a result of oscillations of the density of two-dimensional electron states. They are localized in a quantum well in HgTe near the HgTe/${\mathrm{Hg}}_{0.05}$${\mathrm{Cd}}_{0.95}$Te interface. The experimental dependences of the population of electron bands on the applied bias are compared with the results of numerical calculations carried out on the basis of a three-band Kane model of the energy spectrum. It is shown that two of the three occupied two-dimensional bands, which reveal themselves in our oscillation curves, are two subbands of the lowest electron band which is split by the strong spin-orbit interaction, and the third is one of the split-off subbands of the excited band.