S. V. Kolesnikov

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.

Magnetization dynamics of mixed Co–Au chains on Cu(110) substrate: Combined ab initio and kinetic Monte Carlo study*

We present an investigation of the one-dimensional ferromagnetism in Au–Co nanowires deposited on the Cu(110) surface. By using the density functional theory, the influence of the nonmagnetic copper substrate Cu(110) on the magnetic properties of the bimetallic Au–Co nanowires is studied. The results show the emergence of magnetic anisotropy in the supported Au–Co nanowires. The magnetic anisotropy energy has the same order of magnitude as the exchange interaction energy between Co atoms in the wire. Our electronic structure calculation reveals the emergence of new hybridized bands between Au and Co atoms and surface Cu atoms. The Curie temperature of the Au–Co wires is calculated by means of kinetic Monte Carlo simulation. The strong size effect of the Curie temperature is demonstrated.

Self-organization of iron-atom nanostructures in the first layer of the (100) copper surface

Mechanisms of the diffusion of surface vacancies and iron atoms in the first layer of the Cu(100) surface have been studied by molecular dynamics and the kinetic Monte Carlo method. The diffusion of embedded atoms results in the self-organization of bound iron-atom nanostructures. The time dependences of the number of most widespread nanostructures have been obtained. According to the results, the self-organization of embedded nanostructures can be divided into three stages in which the copper surface has significantly different morphologies.

Magnetic properties of one-dimensional Au-Co chains on the copper(110) surface

Magnetic properties of cobalt atoms in Au-Co chains on the Cu(110) surface (such as the magnetic moment, magnetic anisotropy energy, and exchange energy) have been calculated in the framework of the density functional theory. It has been found, at zero temperature, an infinitely long Au-Co chain is in the ferromagnetic state. The magnetostatic and magnetodynamic properties of finite-length Au-Co chains at a nonzero temperature have been investigated within the Heisenberg model using the kinetic Monte Carlo method. The dependences of the Curie temperature and magnetization reversal time on the chain length have been obtained, as well as the dependences of the coercivity of the chain on the temperature, chain length, and magnetization reversal rate.

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.

Influence of Burrowing the Atoms on the Density of the Fe and Co Nanoclusters on the Cu(100) Surface

The dependence of the density of the Co and Fe clusters on the Cu(100) surface on the substrate temperature and the deposition flux of the atoms has been studied by the molecular dynamics method and the kinetic Monte Carlo method. It has been shown that burrowing the impurity atoms into the first substrate layer can considerably increase the density of nanoclusters. The influence of burrowing the atoms on the size distribution of nanoclusters has been investigated.

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.