Phason elastic constants of the icosahedral Al-Pd-Mn phase derived from diffuse scattering measurements

摘要

The diffuse scattering in the diffraction pattern of the icosahedral Al-Pd-Mn quasicrystalline phase has been measured on an absolute scale by X-ray and neutron scattering on single-grain samples. Most of the diffuse scattering can be interpreted in the framework of the elasticity theory of icosahedral quasicrystals considering only phason fluctuations. At room temperature the absolute values of the K_1/k_BT and K_2/k_BT phason elastic constants are of the order of 0.06 and 0.031 atom~(-1). The amount of diffuse scattering intensity is insensitive to the sample annealing treatment.