E. M. Smelova

Emergence of giant magnetic anisotropy in freestanding Au/Co nanowires

The emergence of giant magnetic anisotropy was found in evenly mixed Au/Co nanowires. First principles molecular dynamics calculations revealed the large values of magnetic anisotropy energy of about ∼130 meV per Co atom in Au/Co nanowires. It was established that the emergence of giant magnetic anisotropy is due to (dxy,dx2) band splitting caused by the strong spin-orbit interaction between gold and cobalt atoms in the wire. It is also shown that the energy of the magnetic anisotropy depends strongly on the geometry and composition of the wire.

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.

Effect of stretching-contraction deformations on the magnetic ordering state of mixed Pd-Fe nanowires

The performed ab initio calculations indicate the possibility of forming stable, uniformly mixed Pd-Fe nanowires. The effect of stretching-contraction deformations on the electronic structure of Pd-Fe nanowires has been revealed. Using the calculation results, a transition from ferromagnetic to antiferromagnetic state in a uniformly mixed Pd-Fe nanowire subjected to tension has been predicted.

Atomic and electronic structure of mixed Au-Co nanowires: Ab initio molecular dynamics study

The atomic and electronic structure of uniformly and nonuniformly mixed Au-Co nanowires have been studied using the ab initio molecular dynamics method. The effect of elastic stretching/contraction deformations on the stability and electronic properties of mixed Au-Co nanowires has been studied. It is established that Co dimers are formed in a nonuniformly mixed nanowire. The formation of CO2 dimers results in a non-uniform distribution of the electron density and interactomic distances along the wire and leads to accelerated rupture of the wire between Au atoms under stretching. Only a uniformly mixed Au-Co nanowire composed of regularly alternating Au and Co atoms is stable under stretching up to large interactomic distances.

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.

Investigation of the mechanical and electronic properties of Ag-Au and Co-Au nanocontacts by the method of first-principle molecular dynamics

The atomic and electronic structures of AgAuAg, AuAgAg, and AuCoCo mixed nanocontacts are investigated by the method of first-principle molecular dynamics. The characteristic interatomic distances in contacts depending on their component composition are determined. The interrelationship between the structural and electronic properties of mixed nanocontacts is shown. The formation of stable bonds between the atoms of various elements in the contact chain, which makes it possible to explain the cause of stabilization and an increase in the contact strength at large interatomic distances is found. It is shown that the addition of Co atoms into pure-gold nanocontacts increases their strength (increases the breaking force of the contact), while the addition of Ag atoms leads to an increase in the range of interatomic distances at which the existence of the nanocontact is possible.

Magnetic characteristics of Au–Mn nanowires

The quantum properties of Au–Mn nanowires are analyzed theoretically from first principles. The emergence of magnetic properties in these nanowires, consisting of nonmagnetic elements, is demonstrated. It is shown that the manganese atoms carry fairly large magnetic moments (∼4.3 μB), although crystalline Mn is a paramagnet. Analysis of the electronic structure of these bimetallic nanowires indicates that the magnetic moments at the Mn atoms arise owing to the formation of a complicated structure of hybrid orbitals. Furthermore, it is found that the antiferromagnetic state in Au–Mn nanowires is stabilized by the occurrence of indirect exchange interaction between Mn atoms.

Electron quantum conductance of bimetallic Pt-Fe nanowires

The magnetic and conducting properties of freestanding Pt-Fe nanowires are investigated by means of molecular dynamics. Our investigation reveals the dependence between a wire’s conductivity and its geometry and magnetic properties. Ab initio calculations show there is no spin polarization of a current in stretched linear Pt-Fe nanowires with antiferromagnetic ordering. Spin polarization of electron transport is observed upon contraction of the wire and is accompanied by its transition into a zig-zag configuration.

Mechanical properties of bimetallic one-dimensional structures

Mechanical properties of freestanding Au-Mn nanowires and Au-Mn nanowire on a Cu (110) substrate are studied with ab initio theoretical approach. The calculations were carried out using the software package Vienna Ab-initio Simulation Package (VASP), which is based on the density functional theory (DFT). It was shown that the breaking force (0.45nN) as well as the interatomic distance at a breaking point in bimetallic nanowire (3.0 Å) are higher than in one component Au wire (0.4 nN and 2.6Å respectively). Relative elongation of 15 % results in a fracture of bimetallic nanowire. We studied the mechanical response of the nanojunction in a form of three-atomic Au chain aligned vertically between two pyramidal gold electrodes and demonstrated that the breaking of nanocontact depends only the interaction between Au atoms in the chain and dependents slightly on the structure and properties of the atomic structure of the electrodes.