Formation of nanosystems under near-equilibrium copper condensation in an ultrapure inert medium

Mechanisms of the self-organization of nanosystems at the condensation of the extremely weak steady flows of copper vapors obtained in magnetron sputtering in an ultrapure argon are studied. It is shown that the free-energy minimization near equilibrium condensation creates prerequisites for the self-organization of statistically homogeneous layers of nanoclusters and determines the transition to the formation of nanosystems in the form of fractal networks. Original Russian Text ? V.I. Perekrestov, A.S. Kornyushchenko, Yu.A. Kosminskaya, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ Fiziki, 2007, Vol. 86, No. 12, pp. 879–883.     

Self-organization of quasi-equilibrium steady-state condensation in accumulative ion-plasma devices

We consider both theoretically and experimentally self-organization process of quasi-equilibrium steady-state condensation of sputtered substance in accumulative ion-plasma devices. It has been shown that the self-organization effect is caused by self-consistent variations of the condensate temperature and the supersaturation of depositing atoms. Two possible types of self-organization process have been found out on the basis of the phase-plane method. The aluminium condensation experimental data confirming the self-organization nature of quasi-equilibrium steady-state condensation are discussed.     

Self-organization and supramolecular chemistry of protein films from the nano-to the macroscale

Experimental data obtained with optical, polarization, scanning electron, and confocal laser microscopes reveal a previously unknown supramolecular modification of protein self-organization (“protos”). This modification arises upon condensation in the open nonequilibrium water-protein system. The process gives rise to the liquid crystal phase of nanostructured eddylike protos films epitaxially growing on the nano-and macrolevels. The model of protein spontaneous self-organization allows one to visualize and study the nonlinear dynamics of condensation and self-organization of protein films with a supramolecular configuration on the nano-and macroscale under abiotic and biotic conditions. This model may help in creating an atlas for protein identification, as well as for diagnostics of pathogenic processes in the living organism that disturb protein self-organization.     

Self-organization of plasma-condensate quasi-equilibrium systems

Physics of the Solid State - The steady-state regime of condensation under conditions close to the phase equilibrium is shown to be provided by the self-organization of the plasma-condensate...     

Bose–Einstein condensation versus Dicke–Hepp–Lieb transition in an optical cavity

We provide an exact solution for the interplay between Bose–Einstein condensation and the Dicke–Hepp–Lieb self-organization transition of an ideal Bose gas trapped inside a single-mode optical cavity and subject to a transverse laser drive. Based on an effective action approach, we determine the full phase diagram at arbitrary temperature, which features a bi-critical point where the transitions cross. We calculate the dynamically generated band structure of the atoms and the associated suppression of the critical temperature for Bose–Einstein condensation in the phase with a spontaneous periodic density modulation. Moreover, we determine the evolution of the polariton spectrum due to the coupling of the cavity photons and the atomic field near the self-organization transition, which is quite different above or below the Bose–Einstein condensation temperature. At low temperatures, the critical value of the Dicke–Hepp–Lieb transition decreases with temperature and thus thermal fluctuations can enhance the tendency to a periodic arrangement of the atoms.     

Variability and Self-Organization in Nanosystems

In supersaturated media nanoparticles grow with fluctuating rate. On a surface of growing nanoparticles a mechanism of synchronization of molecular fluctuations operates increasing their scale up to macroscopic one. Thereof the kinetic equation for states distribution function of nanoparticles approaches the Fokker–Planck equation that is experimentally established on an example of nanoparticles of different nature. In a series of suspensions and aerosols, where the ordered aggregates of nanoparticles are formed, aggregation is multistage process, and at each stage the change of a size distribution function of aggregates is also described by the Fokker–Planck equation. Multistage aggregation is completed by appearance of the particles in system with multilevel hierarchical texture having tendency to accept polyhedral shape. Aforementioned features of nanosystems can be treated as development of variability and ability of systems to self-organization.     

Spontaneous pattern formation in a polariton condensate

Exciton-polariton condensation can be regarded as a self-organization phenomenon, where phase ordering is established among particles in the system. In such condensed systems, further ordering can occur in the particle density distribution, under particular experimental conditions. In this work we report on spontaneous pattern formation in a polariton condensate under nonresonant optical pumping. The slightly elliptical ring-shaped excitation laser that we employ forces condensation to occur into a single-energy state with periodic boundary conditions, giving rise to a multilobe standing-wave patterned state.     

On the problem of nucleation (cell formation) in self-organization of protein nanostructures <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

No convincing theory or hypothesis concerning the origin of biological cells exists today. Insight into the problem is difficult, because an empiric model of cell origination and division at the crucial phase of life, self-organization of protein nanostructures, is lacking. It has been shown experimentally that protein nanostructures exhibit signs of self-organization when an open far-from-equilibrium protein-water system condenses in vitro. In other words, to be active, protein must be in the nonequilibrium state. Such a form of self-organization is accompanied by nucleation and the formation of defects, which divide the protein film into domains (“cells”) with nuclei. This type of structuring in the nonequilibrium (active) protein may be viewed as a crude empiric model of protein nucleation, since it includes the formation and division (self-organization) of biological cells, the origination of which, in turn, is intimately related to the self-organization of protein at the nanolevel. The reason for the similarity of the basic processes is identical conditions of protein condensation in vitro and in vivo. In both cases, when water evaporates rapidly from an open water-protein system that is far from thermodynamic equilibrium, the conditions necessary for protein nonequilibrium nanostructures be self-organized with nucleation in the form of nucleus-containing “cells” are set.     

Tuning a Bisphenol A Lateral Flow Assay Using Multiple Gold Nanosystems

Advanced bisphenol A (BPA) lateral flow assays (LFAs) that use multiple nanosystems are reported. The assays use three nanosystems: gold nanostars, gold nanocubes, and gold nanorods, which are rarely applied in LFAs, compared with general gold nanoparticles that are referred to as gold nanospheres in this paper. These various nanosystems are bound to anti‐BPA antibodies and applied in LFAs to develop advanced BPA LFAs; the developed LFAs show differing BPA detection performance, as well as different visible colors, optical intensities, limits of detection, and application ranges. Advanced BPA LFAs that use multiple gold nano‐object shapes are successfully developed, and the geometry effects of diverse gold nanosystems coupled with anti‐BPA antibodies and the potential applications of regular BPA LFAs are explored.     

Nanostructuring of the submonolayer carbon coatings deposited onto the surface of silicon single crystals in a low-pressure microwave discharge plasma

The surface nanostructuring of the submonolayer carbon coatings deposited onto (111) and (100) silicon wafers in a highly ionized ultrahigh-frequency low-pressure plasma is studied. The effect of the coating thickness and the main processing parameters on the mechanisms of morphological changes is studied with allowance for the reconstruction of a single-crystal silicon surface and the mechanical stresses that appear during the preparation of an atomically clean surface during plasma-chemical etching, heterogeneous condensation, and high-temperature annealing. Integral columnar nanosystems with a density of (4?C5) × 10⁹ cm^?2 and a height of 400 nm are formed on (100) silicon single crystals using nanostructured carbon aggregates as mask coatings and highly anisotropic plasma-chemical etching.     

Giant magnetoresistance effect in hybrid ferromagnetic/semiconductor nanosystems

We theoretically investigate the giant magnetoresistance (GMR) effect in general magnetically modulated semiconductor nanosystems, which can be realized experimentally by depositing two parallel ferromagnetic strips on the top of a heterostructure. Here the exact magnetic profiles and arbitrary magnetization direction of ferromagnetic strips are emphasized. It is shown that a considerable GMR effect can be achieved in such nanosystems due to the significant transmission difference for electrons tunneling through parallel and antiparallel magnetization configurations. It is also shown that the magnetoresistance ratio is strongly influenced by the magnetization direction of ferromagnetic strips in nanosystems, thus possibly leading to tunable GMR devices.     

Condensation in Hamiltonian parametric wave interaction

In the generic Hamiltonian problem of parametric wave interaction, we show theoretically the existence of a sudden transition leading the wave system from completely incoherent states towards highly coherent states. This self-organization process is characterized by a reduction of the nonequilibrium entropy, in contrast with the H theorem of entropy growth inherent to the random phase approximation approach. The mechanism underlying this intriguing condensation process is in essence a reversible nonlinear damping. As a result, the lower the coherence of the initial state, the higher the coherence of the final state.     

Using magnetic resonance characteristics to model the structure of multilayer composite nanosystems

The magnetic resonance characteristics of multilayer composite nanosystems with dielectric, semiconductor, and metal nonmagnetic interlayers are investigated. Analysis of the experimental data shows that the dominant factor determining the magnetic resonance characteristics of multilayer composite nanosystems is the shape of their magnetic granules.     

The possibility of a compensation point induced by a transverse field in transverse Ising nanoparticles with a negative core–shell coupling

The phase diagram and magnetizations of two 2D nanoparticles with a negative core–shell interaction, described by the transverse Ising model, are investigated by the use of the effective field theory with correlations. The behaviors of a compensation point in these nanosystems are examined by changing an applied transverse field. It is proved that a compensation point can be induced in the two nanosystems by applying a transverse field.     

Investigation of gold nanotubes of chiralities (4, 3) and (5, 3) in the Hubbard model

The quantum systems of gold nanotubes of chiralities (4, 3) and (5, 3) have been studied in the framework of the Hubbard model for arbitrary values of the Coulomb interaction and electron concentration. The anticommutator Green’s functions of nanosystems, the energy spectra, and the ground state, ionization, and electron affinity energies have been calculated. The obtained data have been used for comparative analysis of nanosystems.     

Effect of defects in regular nanosystems on interference processes at the reemission of attosecond electromagnetic pulses

The effect of defects in nanostructured targets on interference spectra at the reemission of attosecond electromagnetic pulses has been considered. General expressions have been obtained for calculations of spectral distributions for one-, two-, and three-dimensional multiatomic nanosystems consisting of identical complex atoms with defects such as bends, vacancies, and breaks. Changes in interference spectra by a linear chain with several removed atoms (chain with breaks) and by a linear chain with a bend have been calculated as examples allowing a simple analytical representation. Generalization to two- and three-dimensional nanosystems has been developed.     

Reemission spectra and interference effects upon interaction of ultrashort electromagnetic pulses with nanosystems

The processes of reemission of ultrashort electromagnetic pulses by arbitrary nanosystems consisted of isolated complex atoms have been considered. The angular distributions of reemission spectra have been obtained for a series of regular nanosystems. It has been shown that the interference of the photon-emission amplitudes leads to the appearance of characteristic “diffraction” maxima. One-, two-, and three-dimensional nanostructures, as well as planar and cylindrical constructions as models of planar nanosystems and nanotubes, were used as examples that allow a simple analytical consideration.     

Giant magnetoresistance effect in nanostructures consisting of magnetic–electric barriers

The GMR effect in magnetic–electric barrier nanostructure, which can be realized experimentally by depositing two parallel metallic ferromagnetic strips with an applied voltage on the top of heterostructure, is investigated theoretically. It is shown that a considerable GMR effect can be achieved in such nanosystems due to the significant transmission difference for electrons tunneling through parallel and antiparallel magnetization configurations. It is also shown that the magnetoresistance ratio is strongly dependent upon the applied voltage to metallic ferromagnetic strips in nanosystems, thus may leading to voltage-tunable GMR devices.     

Magnetocaloric Effect in Nanosystems Based on Ferromagnets with Different Curie Temperatures

Journal of Experimental and Theoretical Physics - The magnetocaloric effect in nanosystems based on exchange-coupled ferromagnets with different Curie temperatures is calculated within the...     

Exact solutions for correlation functions of an Ising nanocluster

Using a four-spin nanocluster as an example, a technique for developing exact expressions for correlation functions of Ising-type nanosystems is demonstrated.