Dynamical screening effects in a coupled quasi-one-dimensional electron-phonon system

Abstract

A fully dynamical and finite-lempel'dture study of the electron momenhum relaxation rate and mean free path in a coupled system of electrons and bulk LO phonons in a quantum wire structure is presented. Electmn-electron and electron-phonon interactions are eeated on an &at footing within the leading-order perturbation theoq and random-phase approximation. It is demonstrated that coupled-mode effects drastically change the tramport propties of the system at low temperatures. In panicular. the 'plasmon-like' and 'LO-phonon-like' excitations yield comparable rates which, as a consequence of the singular nahlre of the ID density of states, can be large at the threshold. This is in contrast to room temperature results where oniy the LO-phonon mode conuibutes significantly to the rate. Recent technological advances have led to the realization of electron systems confined essentially in quasi-onedimensional (QlD) structures (quantum wires). These systems, by virtue of their reduced phase space may, in principle, exhibit high carrier mobility [l] which has important implications for high-speed devices. The momentum relaxation rate W R) , r,, for an electron with axial wave vector k , is an important quantity in transport calculations

Optical Phonon Modes and Electron-optical Phonon Interaction in Core-shell Semiconductor Quantum Wires

“…In the past, several workers [10][11][12][13][14][15] had carried out studies of the electron interaction with longitudinal optical (LO) phonons in quantum wires considering the modification of the electron energy spectrum and wave function due to their space localization but assuming the bulk forms for LO phonon modes. However, it was shown that the reduced sized scale and dimensionality have great influence leading to phonon confinement and changes in phonon modes [16][17][18][19].…”