Effect of Oxygen on the Quantum, Magnetic, and Thermodynamic Properties of Co Nanowires on the Reconstructed Anisotropic (1 × 2)/Au(110) and (1 × 2)/Pt(110) Surfaces: Ab Initio Approach

Abstract

Ab initio theoretical study of the quantum magnetic properties of Co nanowires on the pure and oxygen-reconstructed (1 × 2)/Au(110) and (1 × 2)/Pt(110) surfaces is performed. Their structures and electronic configurations are calculated using the electron density functional theory. High values of magnetic moment and magnetic anisotropy energies of Co atoms are found on both pure and oxygen-reconstructed (1 × 2)/Au(110) and (1 × 2)/Pt(110) surfaces. The adsorption of oxygen atoms on the (1 × 2)/Au(110) substrate is shown to affect the structural arrangement of Co nanowire atoms on this substrate and to increase the magnetic anisotropy energy (by 1.91 meV per nanowire atom). The adsorption of oxygen on the Pt(110) substrate substantially decreases the magnetic anisotropy energy of the Co nanowire on it (by 5.98 meV per atom). The origin of these changes is revealed by analyzing the local densities of states of the d electrons of nanowire atoms. The temperature ranges of the states with the lowest free surface energy are determined using the atomistic thermodynamics methods. These data and the available experimental data are used to predict the possibility of observing the structures under study in experiments.