Inelastic Neutron Scattering and Lattice Dynamics of Novel Compounds

Using a combination of lattice dynamical calculations and inelastic neutron scattering experiments, we have studied the phonon properties of a variety of solids. The materials studied find a wide range of applications, which include the negative thermal expansion materials and other technologically important samples, and also geophysically relevant minerals. Often we have made it possible to provide the predictions of the thermal expansion and the equation of state when experimental data are not yet available. It has been shown that a proper description of negative thermal expansion may require consideration of both the acoustic and optic phonon modes in the entire Brillouin zone.