Effects of Electron-Electron Interaction

Abstract

In this chapter we consider some features of transport phenomena caused by the interaction between electrons. As in the previous chapters, the kinetic equation is derived here under the assumption of weak electron-electron interaction. One should take into account that there are important physical situations when this assumption is not valid, and the electron-electron interaction rebuilds the ground state of the electron system and changes the nature of quasiparticles. The kinetic phenomena in such strongly correlated electron systems are not studied in this book. It is important that, in contrast to electron-impurity and electron-boson interactions, the terms linear in the electron-electron interaction (proportional to the square of the electron charge, e²) contribute to the kinetic equation for electrons and describe both the self-consistent (mean) field and exchange effects. The kinetic equation written with this accuracy is used below to study the shift of intersubband resonance in quantum wells and the exciton absorption. The electron-electron scattering is described by the collision integral proportional to e⁴. The matrix elements of electron-electron scattering have to be considered in more detail for the scattering with small momentum transfer, when the effects of dynamical screening are important. The electron-electron interaction can be directly probed by the Coulomb drag between the electrons in closely placed parallel 2D layers.