Lattice dynamics of InAs under hydrostatic pressures

The lattice dynamics of InAs under variable hydrostatic pressures is investigated on the basis of an ‘11-parameter’ rigid-ion model (RIM). The calculated phonon dispersion curves are in satisfactory agreement with the neutron scattering data (available for the TA modes only) measured at room temperature and atmospheric pressure. The one- and two-phonon densities of states functions and mode Gruneisen parameters have been computed at two arbitrary hydrostatic pressures. The effect of high pressure on the phonon dispersion curves is shown to lead to a typical ‘softening’ in the transverse acoustic modes and eventually to a phase trnasformation of the compound.