Lattice Dynamics of GaP under Hydrostatic Pressures

The “eleven‐parameter” rigid‐ion model is used to describe the lattice dynamics of GaP under variable hydrostatic pressures. The one‐phonon and two‐phonon density of states functions are computed for various pressures and compared with the second order Raman spectrum measured by the authors. The effect of high pressure on the phonon dispersion curves is shown to lead to “softening” in the transverse acoustic modes and this suggests a possible driving mechanism for the phase transformation in this compound.