A. L. Klavsyuk

Structure and magnetic properties of Co chains on a stepped Cu surface

Magnetic moments and the magnetic anisotropy energy (MAE) are calculated for Co chains on a stepped Cu(111) surface in a fully relaxed geometry. The Korringa–Kohn–Rostoker Green’s function method is used to determine parameters of N-body interatomic potentials and to fit the semi-empirical tightbinding electronic Hamiltonian. The strain relief at steps and in the Co chains is demonstrated to have a profound effect on the morphology of the substrate. Atomic relaxations are shown to decrease the magnetic moments and the MAE. The MAE and orbital moments are found to exhibit an oscillatory behavior with increasing size of the chains. (Some figures in this article are in colour only in the electronic version)

Simulation of the formation of vacancies upon scanning of Cu(100) surface

The main mechanisms of the formation of vacancies in the first layer of Cu(100) surface have been investigated by the molecular dynamics method. It has been shown that the interaction of the tip of a scanning tunneling microscope with the surface can increase the intensity of the formation of surface vacancies by a factor of 103−105. On the basis of the reported investigations, an effective method has been proposed for controlling the vacancy concentration in the first layer of Cu(100) surface, which does not imply a change in the temperature of the system.

Formation of gold nanocontacts in an ultrahigh vacuum transmission electron microscope: A kinetic Monte Carlo simulation

The effective method for the simulation of self-organization of metal nanocontacts produced in an ultrahigh vacuum transmission electron microscope has been designed. In the framework of this method the main stages of nanocontact formation have been determined. The basic diffusion events which are responsible for the shape of nanocontacts and the time of their formation have been outlined. The self-organization of nanocontacts with different orientation relative to the base fcc lattice has been studied. The results of our simulations are in a good agreement with experimental data.

Molecular dynamics simulation of the formation of metal nanocontacts

The process of the formation of nanocontacts has been studied by the molecular dynamics methods for a group of metals (Cu, Rh, Pd, Ag, Pt, Au). It has been shown that the disruption forces of nanocontacts substantially depend on the orientation ((100), (110), or (111)) of the contact-surface interface. The possibility of forming linear atomic chains as a result of the disruption of nanocontacts has been analyzed for different orientations of the electrode surfaces. The possibility of forming quasi-one-dimensional nanostructures from the Co/Au alloy, which represent a periodic alternation of gold atoms and cobalt trimers, has been predicted.

Molecular Dynamics Study of the Mechanical Properties of Palladium Nanocontacts

The mechanical properties of extended palladium nanocontacts have been investigated by the molecular dynamics method. The characteristic interatomic distances in the contacts have been determined and the process of the formation of palladium atomic contacts undergoing breaking has been studied for the (100), (110), and (111) orientations of the contact-surface interfaces.

Analysis of interactions between Co adatoms on the vicinal Cu(111) surface

The energies of magnetic interactions between Co adatoms at the vicinal Cu(111) surface are calculated in the framework of the density functional theory using the Korringa-Kohn-Rostoker type Green’s functions. It is demonstrated that the interactions between Co adatoms appreciably depend on the distance from a surface step. Our calculations show that the magnitude of the repulsive barrier related to the surface step is larger for Co adatoms located at the upper surface terrace than for those located at the lower surface terrace.

Simulation of the self-organization of nanocontacts in thin gold films

An efficient method has been developed for simulation of the self-organization of metal nanocontacts obtained by transmission electron microscopy. In the framework of this approach, the basic steps of nanocontact formation at room temperature are determined and the main diffusion events determining the contact formation time and the shape of the contacts are revealed. The self-organization of nanocontacts having different orientations with respect to the original fcc lattice is considered. The results obtained are in good agreement with the experimental data on nanocontact formation.

SnSi nanocrystals of zinc-blende structure in a Si matrix

A zinc-blende (sphalerite) crystallographic structure of SnSi nanocrystals generated by molecular-beam epitaxy is observed by electron microscopy techniques in a Si matrix. Ab initio density-functional modeling reveals a stabilizing effect of the Si matrix, which results in the lowest formation enthalpy of SnSi nanocrystals having the unexpected zinc-blende structure. Such nanocrystals could be applied in Si photonics to function as non-centrosymmetric media for the nonlinear optical process of second harmonic generation.

Formation of cobalt bilayer islands on Cu(100) surface

The formation and evolution of Co islands on Cu(100) surface are studied using molecular dynamics simulation and kinetic Monte Carlo method. Two regimes of cluster growth are found. It is revealed that the transition from one growth regime to another is associated with the formation of rectangular Co islands in the first layer. The dependence of the number of Co atoms in the second layer of the cluster on the Co deposition flux at substrate temperatures of 200 and 300 K is studied.

Fe and Co nanostructures embedded into the Cu(100) surface: Self-Organization and magnetic properties

The self-organization and magnetic properties of small iron and cobalt nanostructures embedded into the first layer of a Cu(100) surface are investigated using the self-learning kinetic Monte Carlo method and density functional theory. The similarities and differences between the Fe/Cu(100) and the Co/Cu(100) are underlined. The time evolution of magnetic properties of a copper monolayer with embedded magnetic atoms at 380 K is discussed.