First-Principles Study of the Structural, Electronic, and Magnetic Properties of Cu-Fe, Cu-Co, and Cu-Ni Linear and Zigzag Nanowires

Abstract

By using first-principles calculations, we have systematically investigated the equilibrium structure, electronic, and magnetic properties of free-standing Cu-Fe, Cu-Co, and Cu-Ni bimetallic linear and zigzag nanowires, and a comparison was carried out with the corresponding monatomic chains. It was found that all the bimetallic linear and zigzag chains have stable ferromagnetic (FM) states, and the total energies of all the considered zigzag chains are lower than those of the corresponding linear chains. The equilibrium bond lengths of the bimetallic Cu-Fe, Cu-Co, and Cu-Ni nanowires lie in between the values of the corresponding monatomic systems. The magnetic moments in linear nanowires are generally larger than the ones of the corresponding zigzag nanowires, and the Fe, Co, and Ni atoms in bimetallic nanowires have quite high local magnetic moments. The calculations suggest that there is hybridization between the Cu-3d and Fe (Co or Ni) 3d states, which leads to lower cohesive energies of the bimetallic nanowires than those of the corresponding monatomic nanowires. The bimetallic Cu-Fe and Cu-Co nanowires also have high spin polarizations and may be good potential materials for spintronic devices.