Magnetism of ultrathin nanowires: ab initio study

The results of ab initio calculations within density-functional theory are presented for ultrathin wires composed of fifth and sixth row elements. At first free-standing wires are examined and then, similar to experimental conditions, wires are placed along the step ledges of vicinal silver surfaces. Free-standing wires show mostly a weak tendency towards magnetism at the calculated equilibrium bond lengths. The largest magnetic moments are found for wires with an antiferromagnetic ground state. Unexpectedly, a faint magnetism is predicted also for Pd and the simple metals In and Tl. The epitaxial constraint imposed by the silver substrate induces an increased intrawire bond length favoring magnetic ordering whereas hybridization effects work against magnetism. We find that on Ag substrate most elements tend to antiferromagnetism. The possible growth modes of wires, a row-by-row growth and island formation are discussed.