LO =291.7 cm-1, TO =267.8 cm-1, 
= 11.7, m* = 0.063me. No broadening is assumed here for simplicity. Dispersion of pseudo surface polariton modes at the interface doped / undoped GaAs as a function of the free-carrier concentration n for kx = sin(70°). The two branches (PSP+, PSP-) follow closely those of the longitudinal-optical coupled plasmon-phonon bulk modes (LPP+, LPP-). The horizontal lines indicate the TO and LO frequencies of GaAs. The inset displays the difference between the PSP and LPP modes (PSP+-LPP+: right axis, PSP--LPP-: left axis). Parameters used for calculations are LO =291.7 cm-1, TO =267.8 cm-1, = 11.7, m* = 0.063me. No broadening is assumed here for simplicity.
© 2000 The Materials Research Society
