Effects of impurity and vacancy introduction were investigated by means of first-principles structural relaxation. Studied concentration of the lattice defects was 0.6at%. As the impurity, a Cu atom was substituted for a Zn atom in Zn6Sc. For this concentration, the plausible candidate site of Cu substitution was the glue site distributing in the interstitial region between icosahedral clusters. The most stable vacancy site was the core of the icosahedral cluster. Some of the introduced vacancies migrate several angstrom and reach the core. A special site being outside the core plays an important role for the vacancy migration. The vacancy introduced near this site migrates to the core. Significant Zn-Zn bonds were found in the charge density map. The stability of the defect-introduced structure was discussed in terms of a breaking of this bond.

First-Principles Study for Effect of Lattice Defects on the Crystal Structure of the Zn-Sc Cubic Crystalline Approximant. K.Nozawa, Y.Ishii, K.Makoshi: Journal of Physics - Conference Series, 2010, 226[1], 012031