Influence of band state mixing on interband magnetotunnelling in broken-gap heterostructures

We investigate in detail the effect of electron and light- and heavy-hole state mixing on the transmission coefficients and current-voltage characteristics of interband tunnelling broken-gap heterostructures in the presence of a quantizing magnetic field perpendicular to the interfaces. Double-barrier and barrierless resonant tunnelling structures made from InAs, A1Sb, and GaSb are considered. The multiband Burt envelope function theory and the cylindrical approximation are used to obtain analytical solutions for bulk dispersions, and wavefunctions in heterostructures are derived with the transfer matrix method. Taking into account the mixing of the states of different Landau-level indices at the interfaces due to the spin-orbit interaction, we have calculated the transmission coefficients for the coherent tunnelling transitions between the states of various Landau levels, as well as the corresponding tunnelling current components. We have shown that the mixing with the heavy-hole states results in additional peaks of the current density. The tunnelling processes in which the Landau-level index is not conserved may contribute significantly to these additional peaks.