MICROSCOPIC CALCULATION OF THE ELECTRON OPTICAL-PHONON INTERACTION IN ULTRATHIN GAAS/ALXGA1-XAS ALLOY QUANTUM-WELL SYSTEMS

We have calculated electronoptical-phonon scattering rates in ultrathin GaAs/AlxGa1-xAs alloy quantum-well systems of finite depth, based on a fully microscopic lattice dynamics approach for the phonon spectra. A pseudo-unit-cell model is utilized to calculate the lattice-dynamical properties of the AlxGa1-xAs alloy system together with the two-parameter Keating potential and the long-range Coulomb potential between ions. The polar interactions of quantum confined electrons with GaAs- and AlAs-like optical modes are presented for both intrasubband and intersubband transitions, and the comparison with other theoretical calculations made. Good agreement is obtained for the 11 and 21 transition rates between the microscopic pseuso-unit-cell model and a macroscopic two-pole dielectric continuum model. © 1995 The American Physical Society.