Effect of Uniaxial Stress and Doping on the One‐Phonon Raman Spectrum of GaP

The Raman spectrum of long‐wave optical phonons in n‐type GaP is investigated under the presence of uniaxial stress. The splitting ofthe LO‐phonon is found to be doping‐dependent for (001)‐stress and is explained by phonon—plasmon coupling in connection with repopulation of the electrons. At zero stress the 2 LO‐phonon cut‐off in the second order spectrum does not follow the doping‐induced shift of the LO (k  O) phonon. This indicate avery flat LO‐dispersion curve.