Phonons and electron-phonon interaction in nanostructures

摘要

Based on the Born-Oppenheimer approximation, the electronic properties of solids are described assuming fixed ions. The effect of atomic vibrations around their equilibrium position is then considered as a perturbation. The electron-phonon interaction mechanisms are well established in bulk semiconductors and they reflect the perturbation of electronic states directly by atomic displacements as well as by the electromagnetic field associated to phonons in polar materials. These microscopic mechanisms remain unchanged in nanostructures. However, the effect of electron-phonon interactions is modified in quantum wells, wires and dots due to the quantification along some directions of space of the participating electrons and phonons. We will present in this lecture a review of the existing literature on the basic properties of phonons in bulk semiconductors, on the main electron-phonon mechanisms and on the effect of lateral confinement of phonons on the lattice dynamics. We will also describe several experimental approaches to measure the phonons and the electron-phonon coupling in semiconductors.