On the reduction of the electron-LO phonon scattering in a semiconductor superlattice

The Frohlich coupling of 2D electrons with 2D LO phonons in a semiconductor superlattice is studied. The magnitude of the coupling form factor is remarkably reduced by reducing the layer width. The electron self-energy due to the polar interaction is studied as a function of the 2D kinetic energy. The scattering rate given by the imaginary part of the self-energy shows an abrupt threshold at optical phonon energy, but the magnitude is smaller than that for 2D electron and 3D phonon systems. It is shown that the inter-sub-band transition and the remote phonon interaction contribute a small fraction to the total scattering rate.