On the energy ratio between the phonon and the phason part of dislocations in icosahedral Al-Pd-Mn quasicrystals

Using two different ansätze for the energy of quasicrystal dislocations the phonon strain energy is related to the phason strain energy by means of the strain energy ratio. The possible ranges for this ratio are determined while a new type of dislocation dissociation is proposed. This reaction describes the dissociation of a perfect dislocation into two other also perfect dislocations. Based on recent experimental observations the energy ratio due to phason and phonon strain of dislocations with Burgers vectors along twofold directions is calculated. Also recent experimental observations of partial dislocations are considered. Implications for the mechanisms stabilizing the quasicrystalline structures are discussed.