Investigation of the direct/indirect exciton transition in the double quantum well system based on Cd₁₋yMgyTe/ Cd₁₋xMnxTe in applied magnetic field

Abstract

The energy levels, wave functions, and lifetimes of direct and indirect excitons in a CdTe-based double quantum well system with non-magnetic (Mg) and magnetic (Mn) ions in a magnetic field are found. It is shown that, in an external magnetic field greater than some critical value, the lowest excited state of the system becomes the indirect exciton state. Since the indirect exciton lifetime exceeds the direct exciton one by a few orders of magnitude, the magnetic field can significantly influence optical properties of the system (for example, the luminescence intensity). The realistic range of parameters of a quantum well (well and barrier widths, Mn and Mg concentrations, the magnetic field strength), in which the exciton lowest state is the indirect exciton state, is calculated.