Magnetic properties of Pd atomic chains formed during submonolayer deposition of 3d metals on Pd(110).

Recently, an unusual intermixing-driven scenario for the growth of atomic Pd chains on a Pd(110) surface during deposition of 3d metal atoms has been predicted (Stepanyuk 2009 Phys. Rev. B 79 155410) and confirmed by STM and STS experiments (Wie et al 2009 Phys. Rev. Lett. 103 225504). Performing ab initio calculations we demonstrate that Pd atomic chains grown above embedded Fe atoms exhibit magnetic properties which depend on the substrate mediated exchange interaction between the Fe atoms.

Electric field as a switching tool for magnetic states in atomic-scale nanostructures.

One of the most promising candidates for the construction of ultrahigh-density storage media is low-dimensional atomic-scale magnetic nanostructures exhibiting magnetic bi- or multistability. Here we propose a novel route of locally controlling and switching magnetism in such nanostructures. Our ab initio studies reveal that externally applied electric field can be used for this purpose.

Melting of two-dimensional adatom superlattices stabilized by long-range electronic interactions.

The melting transition of Ce adatom superlattices stabilized by long-range substrate-mediated electronic interactions on Cu(111) and Ag(111) noble metal surfaces has been investigated by low-temperature scanning tunneling microscopy, density functional theory calculations, and kinetic Monte Carlo simulations. Intriguingly, owing to the interaction between Ce adatoms and substrate, these superlattices undergo two-dimensional melting to a liquid without transition through the hexatic phase. The crucial parameters for this direct solid to liquid transition are identified.

Direct evidence for the effect of quantum confinement of surface-state electrons on atomic diffusion.

We report on the direct observations of the effect of quantum confinement of surface-state electrons on atomic diffusion. Confined electronic states induced by open nanoscale resonators [consisting of two parallel monatomic Cu chains on Cu(111)] are studied by means of scanning tunneling microscope measurements and first-principles calculations. Strongly anisotropic diffusion of adatoms around and inside resonators is revealed at low temperatures. The formation of diffusion channels and empty zones is demonstrated. We show that it is possible to engineer atomic diffusion by varying the distance between the resonator walls.

Buried Ni/Cu(001) interface at the atomic scale.

We present a quantitative surface x-ray analysis of the buried Ni/Cu(001) interface structure after deposition of 3 and 5 monolayers of Ni at room temperature. Interface mixing is found where 27+/-10% of top layer Cu atoms are exchanged by Ni. Atomic scale simulations reveal a kinetic pathway for the Ni/Cu-exchange process and explain the observed limited degree of intermixing. A disperse distribution of Ni within the Cu surface with a preferential Ni-Ni separation of 3-4 nearest neighbor distances is determined.

Adatom self-organization induced by quantum confinement of surface electrons.

We present a novel mechanism of nanostructure growth based on quantum confinement of surface-state electrons. Ab initio calculations and the kinetic Monte Carlo simulations reveal the phenomenon of confinement-induced adatom self-organization in quantum corrals. Our studies indicate that new atomic-scale nanostructures can be engineered exploiting the quantum confinement of surface electrons.