PHONON CONFINEMENT AND SCREENING EFFECTS ON THE POLARON ENERGY IN QUANTUM WIRES

We study the contribution of confined phonons to the polaron energy in quantum-well wires. We use a dispersionless, macroscopic continuum mo del to describe the phonon confinement in quantum wires of square cros s section. The polaron energy is calculated variationally incorporatin g the dynamic screening effects. We find that the confined phonon cont ribution to the polaron energy is comparable to that of bulk phonons i n the density range N = 10(4)-10(7) Cm-1. Screening effects within the random-phase approximation significantly reduce the electron-confined phonon interaction, whereas the correlation effects tend to oppose th is trend.