Frequency-Shifted Polaron Coupling inGa0.47In0.53As Heterojunctions

Abstract

Frequency-dependent cyclotron-resonance measurements are reported on ${\mathrm{Ga}}_{0.47}$ ${\mathrm{In}}_{0.53}$As-InP and ${\mathrm{Ga}}_{0.47}$ ${\mathrm{In}}_{0.53}$ ${\mathrm{A}\mathrm{s}-\mathrm{A}\mathrm{l}}_{0.48}$ ${\mathrm{In}}_{0.52}$As heterojunctions. Discontinuities in the effective mass occur at two frequencies as a result of resonant polaron coupling with both optic-phonon modes present in the ${\mathrm{Ga}}_{0.47}$ ${\mathrm{In}}_{0.53}$As alloy. The coupling occurs at the frequencies at the TO phonons, in contrast to measurements on bulk materials. Possible changes in the screening and polarization of the optic-phonon modes are considered.