OPTICAL-PHONON MODES AND ELECTRON-OPTICAL-PHONON INTERACTION IN A COUPLED QUANTUM WELL
SHI JUN-JIE
China Center of Advanced Science and Technology (CCAST) (World Laboratory), Beijing 100080, China; Department of Physics, Henan Normal University, Xinxiang 453002, China
Abstract By applying the dielectric continuum model, optical-phonon modes of the lattice vibration and a complete interaction Frohlich-like Harniltonian between an electron and the optical phonons including the interface phonons, the confined LO phonons and the half-space LO phonons are derived for a general coupled quantum well (GCQW) structure of polar crystals. The dispersion curves of the interface modes and the electron-interface-phonon coupling function as functions of coordinate z and wavenumber k are given and discussed for a GCQW. We find that there are eight (not ten) frequency solutions for the interface optical-phonon modes in GCQW and that, in the long-wavelength limit, the longitudinal and transverse modes in the two side materials 1 and 5 are forbidden and two new frequency solutions ω± are obtained instead. Moreover, we also find that the electron-interface-phonon coupling functions are complicated functions of k and that the phonons with long wavelengths are important and the higher-frequency modes are more important than the lower-frequency modes for the electron-phonon interaction.
Received: 12 July 1995
Revised: 09 October 1995
Published: 20 June 1996
PACS:
63.22.-m
(Phonons or vibrational states in low-dimensional structures and nanoscale materials)
