For the last decade, active research on magnetic nanosystems of curved geometry was motivated by their outstanding properties and great application potential [1]. For instance, recent theoretical studies of low-dimensional magnets with complex geometry propose a description of fascinating geometry-induced effects including pattern formation and magnetochiral effects in quasi-one-dimensional...
We consider the spin-1/2 antiferromagnetic Heisenberg model on one-dimen-sional frustrated lattices (double tetrahedra chain [1], deformed octahedral chain [2]) placed in an external magnetic field with almost dispersionless (almost flat) lowest magnon band. The main goal of our study is to develop a systematic theory for the low-temperature high-field properties of these models, using the...
We consider the quantum antiferromagnetic Heisenberg model on the square-lattice and honeycomb-lattice bilayers in the absence of an external magnetic field. We use a variational approach to construct the ground-state phase diagrams of such model on different bilayers. For simplicity, we choose two one-parameter variational wave functions, which can describe states of model in two regions with...
To calculate the current-phase relation in superconducting junctions, it is necessary to investigate the spatial behavior of the order parameter in the superconducting regions of the junction. In the case of temperatures close to the critical one, the Ginzburg-Landau theory [1] is used for this purpose. However, to apply this theory there is necessary to find the corresponding boundary...
The explored layered superconducting structure contains three massive superconductors separated by two thin insulator films. Without loss of generality we may consider that the superconductors are different. An insulator film is mathematically expressed via the Dirac delta function [1]. An order parameter and a current density depend on an applicate, because we have a one dimensional...
It is predicted that oscillations of temperature during propagation of third sound in a thin superfluid film cause appearance of an alternating electric field in the surrounding space, i.e. the third sound acts as a generator of the electric field [1].
As known, the helium atoms have no dipole, quadrupole and other multipole moments. The situation changes in the vicinity of the wall....
Understanding of light-matter interaction in a wide frequency range is an important fundamental problem with significant potential applied impacts. For instance, Plasmonics is a rapidly developing field at the boundary of physical optics and condensed matter physics with many prospective applications. However, the use of plasmons is limited from a practical point of view because their spectral...
Optical conductivity spectra are studied for the Falicov-Kimball model with correlated hopping on the Bethe lattice. An expression for the current-current correlation function is derived using dynamical mean field theory. Besides, the Nyquist plots were built and used to distinguish different contributions in the optical conductivity spectra.
In the metallic phase without correlated hopping,...
The standard effective-medium methods to electrodynamic homogenization of heterogeneous media can be divided into two classes: symmetrical and asymmetrical. They are assumed to be independent and applicable to different types of systems, making a basis for different further modifications that take into account specific features of a given system. Despite the fact that these modifications are...
Tuning of thermal properties of various materials is a key challenge in material research. First and foremost, such necessity arises because of continuous miniaturization of constitute components of various devises. As a result, issue connected with amelioration of heat management started to be more and more crucial. Therefore, any possibilities of increasing or reduction of thermal...
