Dependence of Raman frequencies and scattering intensities on pressure in GaSb, InAs, and InSb semiconductors

The first-order Raman scattering by TO and LO phonons has been measured in GaSb, InAs, and InSb under hydrostatic pressures up to their phase transitions. The Raman frequencies increase nearly linearly while the LO-TO splitting decreases with increasing pressure. The scattering intensities display strong enhancement as the E₁ band gaps approach the laser frequencies with increasing pressure. The measured volume dependence of the Raman frequencies and the transverse effective charges is interpreted by means of pseudopotential calculations. The resonance behavior is discussed in terms of resonant Raman scattering near the E₁ gaps.