Dynamical properties of icosahedral quasicrystal and glassy Al₇₇Cu₁₃V₁₀: A comparative study by inelastic neutron scattering

According to the structural study of the icosahedral quasicrystal and glassy Al₇₇Cu₁₃V₁₀, it has been shown that these two materials have the same nanoscale structure unit, namely, the icosahedral atomic cluster. However, the glassy material has a dense random-packing structure which is composed of the icosahedral atomic clusters, without any long-range orientational ordering. Therefore, the icosahedral quasicrystal and glassy Al₇₇Cu₁₃V₁₀ are interesting samples for studying the dynamical properties of disordered materials. We have measured the dynamical structure factors S(Q,ω) of icosahedral and glassy Al₇₇Cu₁₃V₁₀, and the crystallized sample at room temperature by means of inelastic neutron scattering. Measurements were performed on the inverted geometry crystal-analyzer type time-of-flight spectrometers LAM-40, which is installed at KENS. The generalized vibrational density of states G(ω) were also obtained. The low-energy excitation modes in icosahedral and glassy Al₇₇Cu₁₃V₁₀ were observed in the energy range below 8 meV. In contrast to the significant difference observed in the static structure factors S(Q) of icosahedral and glassy Al₇₇Cu₁₃V₁₀, their dynamical properties are nearly identical and quite different from that of the crystallized sample.