Bottleneck in electron-electron interactions and anomalies in the Landau quantization damping

Electron-electron interactions in a single highly doped heterojunction are considered taking into account both intra- and intersubband transitions. Expressions are derived for the time of electron-electron interaction, matrix elements of the full screening potential and dynamic dielectric function in a 2D electron system with the fine structure of the energy spectrum, and for the electron density spatial distribution. The calculated dependences tau(ee)(th)(T, n(s)) provide a good description of the experimental times of Landau levels collisional broadening tau(q)(exp)(T, n(s)). The dielectric function spectrum chi(q, w) was found to contain resonances positioned around the regions with developed fine structure of electron density.