Origin of structure inversion asymmetry in double HgTe quantum wells

The density dependences of the splitting values of the dominant magneto-absorption lines in undoped $p$-type double HgTe/CdHgTe quantum wells are studied. An analysis of the splitting values of the magneto-absorption lines on the basis of self-consistent calculations of the band structure has made it possible to clarify the origin of structure inversion asymmetry in double HgTe/CdHgTe quantum wells and to determine the contributions caused by the built-in electric field, the difference between the thicknesses of the quantum wells, and the order of their arrangement in the structure. The discrepancy between the experimental energy splitting of the zero-mode Landau levels, extracted from the analysis of two types of lines, indicates the influence of many-particle effects on the transition energies between Landau levels.