Vol 106, No 4 (2017)

We review our recent theoretical results for mesoscopic fluctuations of the local density of states in the presence of electron–electron interaction. We focus on the two specific cases: (i) a vicinity of interacting critical point corresponding to an Anderson–Mott transition, and (ii) a vicinity of non-interacting critical point in the presence of a weak electron–electron attraction. In both cases, strong mesoscopic fluctuations of the local density of states exist.

Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up–down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

The magnetic properties of Co-adsorbed SiC monolayer under an external electric field are investigated using first-principles method. In the absence of the electric field, the interaction between two Co atoms is ferromagnetic, which is originated by the p−d hybridization between Co and its neighboring C and Si atoms. When an electric field was introduced along the c axis, the interaction between two Co dopants switched from ferromagnetic to antiferromagnetic, which could be dominated by the competition between p−d exchange and superexchange. Moreover, the magnetic anisotropy prefers to parallel to the a axis and it seems not to be turn into the c axis under the electric field.

The initial stage of the adsorption of Ge on an Au(111) surface was investigated. The growth and stability of the structures formed at the surface were studied by ultrahigh-vacuum low-temperature scanning tunneling microscopy and analyzed using density functional theory. It was established that the adsorption of single Ge atoms at the Au(111) surface at room temperature leads to the substitution of Au atoms by Ge atoms in the first surface layer. An increasing of surface coverage up to 0.2–0.4 monolayers results in the growth of an amorphous binary layer composed of intermixed Au and Ge atoms. It was shown that the annealing of the binary layer at a temperature of T_s ≃ 500 K, as well as the adsorption of Ge on the Au(111) surface heated to T_s ≃ 500 K for coverages up to 1 monolayer lead to a structural transition and the formation of an Au–Ge alloy at least in the first two surface layers. Based on experimental and theoretical data, it was shown that the formation of single-layer germanene on the Au(111) surface for coverages ≤1 monolayer in the temperature range of T_s = 297–500 K is impossible.

A time-nonlinear stage of the collapse of islands in freely suspended smectic nanofilms is observed and investigated. Islands thicker than a nanofilm are prepared and studied, which are unstable inside the dislocation loops, since they increase the energy of the film. Such instability leads to the decrease in the size of islands and is terminated by their collapse. The time dependence of the size of islands is measured experimentally. It is shown that the found dependence is in agreement with the theory of the dynamics of dislocation loops in smectic films developed earlier with allowance for the dissipation of energy in the film and in the meniscus. A nontrivial dynamic coupling between islands in a film resembling Ostwald ripening is also found, though the nonequilibrium kinetics of unstable islands, at which the hydrodynamic flow through a film leads to the decrease in sizes of one island and the increase in those of the other, rather than of the growth of the nucleation centers in the thermodynamically stable phase from the metastable state of the system (described by the Lifshitz–Slezov theory in films), is studied in our experiments.

Ab initio calculations of the electronic structure and frequency dependence of the imaginary part of the dielectric function for 1–2 nm silicon nanocrystals with the surface fully passivated with Cl or Br halogen atoms have been performed. According to these calculations, passivation with halogens results in the strong localization of valence electrons near the surface. As a result, the width of the band gap of a nanocrystal is noticeably narrowed and its absorptance decreases as compared to the case of hydrogen passivation. These effects are more pronounced in bromine-passivated nanocrystals.

A dusty plasma formed in chain exothermal reactions initiated by radiation of a high-power gyrotron in mixtures of metal and dielectric powders has been described. An oscillatory character of such chain reactions, as well as the appearance of dust particles at the first (explosive) stage, has been detected. The tracks, velocities, and sizes of dust particles have been measured. It has been revealed that ensembles of dust particles appear in a reactor after switching-off of the gyrotron against the background of development of chemical reactions. The time of existence of these ensembles is three or four orders of magnitude larger than the duration of a microwave radiation pulse. The quasistationary state of the low-temperature plasma with charged macroparticles appears because of both the chemical heating of the mixture in the reactor and thermophoresis. It has been shown that dust particles are necessary as crystallization nuclei for the creation (or deposition) of complex composites of nano- and micromaterials produced in secondary plasma chemical synthesis.