Core–shell and matryoshka structures in MgNi nanoalloys: a computational study

Abstract

The structures of MgNi nanoparticles are searched for by a computational methodology combining atomistic modeling, global optimization searches and density-functional theory (DFT) calculations. Sizes of up to 45 atoms are considered for several different compositions. Core–shell structures are found in most cases. However, there are also exceptions, such as the three-shell high-symmetry matryoshka clusters Mg@Ni₁₂@Mg₃₂ (of anti-Mackay icosahedral geometry) and Mg@Ni₁₂@Mg₁₄ (of tetrahexahedral geometry). Other high-symmetry structures comprise the core–shell cubic Mg₈Ni₆, the tetrahexahedral cluster Mg₁₄Ni₁₃ and the pentadocahedral cluster Mg₂₁Ni₁₂. The results of the atomistic models are compared with DFT calculations, obtaining a good agreement.