Topological coupling of dislocations and magnetization vorticity in Spin Density Waves

The rich order parameter of Spin Density Waves allows for an unusual object of a complex topological nature: a half-integer dislocation combined with a semi-vortex of the staggered magnetization. It becomes energetically preferable to ordinary dislocation due to enhanced Coulomb interactions in the semiconducting regime. Generation of these objects changes the narrow band noise frequency.Comment: To be published in Proceedings of ECRYS-99, J. de Physique, Coll., December 1999. http://ipnweb.in2p3.fr/~lptms/membres/brazov

Topological Defects in Spin Density Waves

The rich order parameter of Spin Density Waves allows for unusual object of a complex topological nature: a half-integer dislocation combined with a semi-vortex of a staggered magnetization. It becomes energetically preferable to ordinary dislocation due to enhanced Coulomb interactions in the semiconducting regime. Generation of these objects changes e.g. the narrow band noise frequency.Comment: 9 pages, 2 figure

Observation of correlations up to the micrometer scale in sliding charge-density waves

High-resolution coherent x-ray diffraction experiment has been performed on the charge density wave (CDW) system K$_{0.3}$MoO$_3$. The $2k_F$ satellite reflection associated with the CDW has been measured with respect to external dc currents. In the sliding regime, the $2k_F$ satellite reflection displays secondary satellites along the chain axis which corresponds to correlations up to the micrometer scale. This super long range order is 1500 times larger than the CDW period itself. This new type of electronic correlation seems inherent to the collective dynamics of electrons in charge density wave systems. Several scenarios are discussed.Comment: 4 pages, 3 figures Typos added, references remove

Multi-vortex dynamics in junctions of charge density waves

Ground state reconstruction by creation of topological defects in junctions of CDWs is a convenient playground for modern efforts of field-effect transformations in strongly correlated materials with spontaneous symmetry breakings. Being transient, this effect contributes also to another new science of pump-induced phase transitions. We present a dynamical model for behavior of the CDW in restricted geometries of junctions under an applied voltage or a passing current. The model takes into account multiple interacting fields: the amplitude and the phase of the CDW complex order parameter, distributions of the electric field, the density and the current of various normal carriers. A particular challenge was to monitor the local conservation of the condensed and the normal charge densities. That was done easily invoking the chiral invariance and the associated anomaly, but prize is an unconventional Ginsburg-Landau type theory which is not analytic with respect to the order parameter. The numerical modeling poses unusual difficulties but still can demonstrate that vortices are nucleated at the junction boundary when the voltage across, or the current through, exceed a threshold.Comment: To be published in proceedings of the conference SUPERSTRIPES-2014, A. Bianconi ed., J. Supercond. Nov. Mag., (2015

Coulomb interaction and electron-hole asymmetry in cyclotron resonance of bilayer graphene in high magnetic field

Inter-Landau-level transitions in the bilayer graphene at high perpendicular magnetic field at the filling-factor v<<1 have been studied. The next-nearest-neighbor transitions, energy difference between dimer and non-dimer sites and layer asymmetry are included. The influence of Coulomb interaction is taken into account. The magnetoplasmon excitations in bilayer graphene at small momenta are considered in the frame of the Hartree-Fock approximation. It is shown that asymmetry in cyclotron resonance of clean bilayer graphene depends on magnetic field. At lower magnetic fields the energy splitting in the spectrum is due to electron-hole one-particle asymmetry, at higher magnetic fields the energy splitting in the spectrum is due to Coulomb interaction. For the fullsymmetric case with half-filled zero-energy levels the energy splitting proportional to the energy of Coulomb interaction is found both for bilayer and monolayer graphene.Comment: 6 pages, 2 figure

METHOD OF ESTIMATION OF ENVIRONMENTAL HAZARD OF URBAN LAND USING FOR VITAL ACTIVITY OF POPULATION

It is noted that the global updating of the ecological problems at the end of the XX - the beginning of the XXI centuries, the undeniable importance of the ecological component of human existence, causes the urgent need for a balanced, holistic, integrated approach to the analysis and solution of issues of ensuring the ecological safety of the vital activities of the population, including the city. At the same time, at the legislative level, environmental safety is identified as one of the priority tasks in the state policy of Ukraine in order to achieve sustainable development. It is proved that the provision of environmental safety remains the main way of solving ecological problems, which guarantees citizens the development and living in harmony with the environment and opens up new opportunities for other forms of activity in the field of nature management, in particular, political, economic, social, etc. The methodical approach to an estimation of ecological danger of urban land use for vital activity of the population and typification of land use of green plantings is grounded. An assessment of the state of ecological danger for the city of Kiev is given. On the basis of the proposed methodical approach, it is justified that today there are threats to the ecological stability of land use, and accordingly, environmental insecurity of land use, which indicates a lack of change in the structure of land use for many years

TRANSFORMATION OF THE RUSSIAN TAX SYSTEM IN THE CONTEXT OF ESTABLISHMENT OF THE DIGITAL ECONOMY

The controversial issues of a new approach to solving the problem of transformation of the tax system of the Russian Federation in the context of establishment of the digital economy have been considered. The problems of converting the tax system of the Russian Federation in digital reality and search for approaches to their solution have been identified. The methods of systematic approach, analysis and synthesis, as well as abstraction and generalization have been used. Due to the use of modern business models, carrying- out business activities without registration and the actual presence in the country, tax risks of tax evasion are increasing. The conclusions have been made about the need to identify new emerging economic relations and their legal consolidation, development and implementation of effective tax policy, and on its basis the transformation of the tax system

Probing Spin-Charge Relation by Magnetoconductance in One-Dimensional Polymer Nanofibers

Polymer nanofibers are one-dimensional organic hydrocarbon systems containing conducting polymers where the non-linear local excitations such as solitons, polarons and bipolarons formed by the electron-phonon interaction were predicted. Magnetoconductance (MC) can simultaneously probe both the spin and charge of these mobile species and identify the effects of electron-electron interactions on these nonlinear excitations. Here we report our observations of a qualitatively different MC in polyacetylene (PA) and in polyaniline (PANI) and polythiophene (PT) nanofibers. In PA the MC is essentially zero, but it is present in PANI and PT. The universal scaling behavior and the zero (finite) MC in PA (PANI and PT) nanofibers provide evidence of Coulomb interactions between spinless charged solitons (interacting polarons which carry both spin and charge)

Wigner crystallization in a polarizable medium

We present a variational study of the 2D and 3D Wigner crystal phase of large polarons. The method generalizes that introduced by S. Fratini,P.\ Qu{\'{e}}merais [Mod. Phys. Lett. B {\bf 12} 1003 (1998)]. We take into account the Wigner crystal normal modes rather than a single mean frequency in the minimization procedure of the variational free energy. We calculate the renormalized modes of the crystal as well as the charge polarization correlation function and polaron radius. The solid phase boundaries are determined via a Lindemann criterion, suitably generalized to take into account the classical-to-quantum cross-over. In the weak electron-phonon coupling limit, the Wigner crystal parameters are renormalized by the electron-phonon interaction leading to a stabilization of the solid phase for low polarizability of the medium. Conversely, at intermediate and strong coupling, the behavior of the system depends strongly on the polarizability of the medium. For weakly polarizable media, a density crossover occurs inside the solid phase when the renormalized plasma frequency approaches the phonon frequency. At low density, we have a renormalized polaron Wigner crystal, while at higher densities the electron-phonon interaction is weakened irrespective of the {\it bare} electron-phonon coupling. For strongly polarizable media, the system behaves as a Lorentz lattice of dipoles. The abrupt softening of the internal polaronic frequency predicted by Fratini and Quemerais is observed near the actual melting point only at very strong coupling, leading to a possible liquid polaronic phase for a wider range of parameters.Comment: 24 pages, 13 figures v1.