Effects of parallel electric and magnetic fields on Rydberg excitons in buckled two-dimensional materials

We study direct and indirect magnetoexcitons in Rydberg states in monolayers and double-layer heterostructures of Xenes (silicene, germanene, and stanene) in external parallel electric and magnetic fields, applied perpendicular to the monolayer and heterostructure. We calculate binding energies of magnetoexcitons for the Rydberg states 1$s$, 2$s$, 3$s$, and 4$s$, by numerical integration of the Schr\"{o}dinger equation using the Rytova-Keldysh potential for direct magnetoexciton and both the Rytova-Keldysh and Coulomb potentials for indirect excitons. Latter allows understanding a role of screening in Xenes. In the external perpendicular electric field, the buckled structure of the Xene monolayers leads to appearance of potential difference between sublattices allowing to tune electron and hole masses and, therefore, the binding energies and diamagnetic coefficients (DMCs) of magnetoexcitons. We report the energy contribution from electric and magnetic fields to the binding energies and DMCs. The tunability of the energy contribution of direct and indirect magnetoexcitons by electric and magnetic fields is demonstrated. It is also shown that DMCs of direct excitons can be tuned by the electric field, and the DMCs of indirect magnetoexcitons can be tuned by the electric field and manipulated by the number of h-BN layers. Therefore, these allowing the possibility of electronic devices design that can be controlled by external electric and magnetic fields and the number of h-BN layers. The calculations of the binding energies and DMCs of magnetoexcitons in Xenes monolayers and heterostructures are novel and can be compared with the experimental results when they will be available.Comment: 20 pages, 9 figure

Magnetoexcitons in transition-metal dichalcogenides monolayers, bilayers, and van der Waals heterostructures

We study direct and indirect magnetoexcitons in Rydberg states in monolayers and heterostructures of transition-metal dichalcogenices (TMDCs) in an external magnetic field, applied perpendicular to the monolayer or heterostructures. We calculate binding energies of magnetoexcitons for the Rydberg states 1$s$, 2$s$, 3$s$, and 4$s$ by numerical integration of the Schr\"{o}dinger equation using the Rytova-Keldysh potential for direct magnetoexcitons and both the Rytova-Keldysh and Coulomb potentials for indirect magnetoexcitons. Latter allows understanding the role of screening in TMDCs heterostructures. We report the magnetic field energy contribution to the binding energies and diamagnetic coefficients (DMCs) for direct and indirect magnetoexcitons. The tunability of the energy contribution of direct and indirect magnetoexcitons by the magnetic field is demonstrated. It is shown that binding energies and DMCs of indirect magnetoexcitons can be manipulated by the number of hBN layers. Therefore, our study raises the possibility of controlling the binding energies of direct and indirect magnetostrictions in TMDC monolayers, bilayers and heterostructures using magnetic field and opens an additional degree of freedom to tailor the binding energies and DMCs for heterostructures by varying the number of hBN sheets between TMDC layers. The calculations of the binding energies and DMCs of indirect magnetoexcitons in TMDC heterostructures are novel and can be compared with the experimental results when they will be available.Comment: 21 pages, 9 figures, 6 tables. arXiv admin note: text overlap with arXiv:2011.0309

Magnetoexcitons in phosphorene monolayers, bilayers, and van der Waals heterostructures

We study direct and indirect excitons in Rydberg states in phosphorene monolayers, bilayer and van der Waals (vdW) heterostructure in an external magnetic field, applied perpendicular to the monolayer or heterostructure within the framework of the effective mass approximation. Binding energies of magnetoexcitons are calculated by a numerical integration of the Schrodinger equation using the Rytova-Keldysh potential for direct magnetoexcitons and both the Rytova-Keldysh and Coulomb potentials for indirect one. The latter allows to understand the role of screening in phosphorene. We report the magnetic field energy contribution to the binding energies and diamagnetic coefficients (DMCs) for magnetoexcitons that strongly depend on the effective mass of electron and hole and their anisotropy and can be tuned by the external magnetic field. We demonstrate theoretically that the vdW phosphorene heterostructure is a novel category of 2D semiconductor offering a tunability of the binding energies of magnetoexcitons by mean of external magnetic field and control the binding energies and DMCs by the number of hBN layers separated two phosphorene sheets. Such tunability is potentially useful for the devices design.Comment: 13 pages 5 figures, 5 tables. arXiv admin note: text overlap with arXiv:2012.0712

On superfluidity of indirect excitons in transition metals trichalcogenides van der Waals heterostructures

We predict angle-dependent superfluidity for a new class of 2D materials -- transition metals trichalcogenides (TMTC). Within a mean-field approach superfluidity of indirect excitons in TMTC van der Waals heterostructures (vdWHs) is studied. We use different potentials for charged carriers interaction to analyze the influence of the screening on the studied phenomena. Our study demonstrates the angle-dependent superfluidity temperature in TMTC vdWHs: for a given density a maximum and minimum $T_c$ of superfluidity occurs along chain and $a$-directions, respectively. This work can guide experimental research toward the realization of anisotropic superfluidity in TMTC vdWH. We suggest an experiment for the observation of anisotropic superfluidity in TMTC vdWH.Comment: 10 pages, 2 figure

The Study of Excitons in 2D Novel Materials and Their van der Waals Heterostructures in the Magnetic Field

This research focuses on the direct and indirect excitons in Rydberg states in monolayers, bilayers, and van der Waals heterostructures composed of 2D semiconductors in the presence of the external magnetic field. In our work, we report binding energies of direct and indirect excitons in Rydberg states, the energy contribution from the magnetic field to the binding energies of magnetoexcitons, and diamagnetic coefficients (DMCs) of magnetoexcitons. We study isotropic materials: transition metal dichalcogenides, TMDCs (WSe2, WS2, MoSe2, MoS2), and Xenes (silicene, germanene, stanene), and anisotropic materials: phosphorene and transition metal trichalcogenides, TMTCs (TiSe3, TiS3, ZrSe3, ZrS3). For excitons in TMDCs, phosphorene, and TMTCs, we consider freestanding (FS) and encapsulated by hexagonal boron nitride (hBN) monolayers, FS bilayers, and van der Waals heterostructures (vdWHs) when the external magnetic field is perpendicular to the structure. In vdWHs, the top and bottom 2D semiconductor monolayers are separated by the number of hBN layers, N. For excitons in Xenes, we consider FS and hBN-encapsulated monolayers and vdWHs when the external electric and magnetic fields are perpendicular to the structure. Excitons in TMDCs and Xenes structures are studied when the external magnetic field is varied between 0 and 30 T, and for Xenes, the electric field is taken above the critical value which is unique for each material up to the value where a Xene monolayer becomes unstable. Excitons in TMTCs and phosphorene structures are studied when the magnetic field is varied between 0 and 60 T. In our approach, within the framework of the effective mass approximation, we solve the Schrodinger equation for an interacting electron and hole. For direct excitons in a monolayer, we use the Rytova-Keldysh (RK) potential to describe interactions between an electron and hole. For indirect excitons in a bilayer and vdWH, we use the Rytova-Keldysh and Coulomb potentials to describe interactions between an electron and hole located in two different monolayers. This allows us to investigate the role of the screening in TMDCs, Xenes, TMTCs, and phosphorene. We show that the energy contribution from the magnetic field to the binding energies and DMCs of direct and indirect magnetoexcitons can be tuned by the magnetic field. For magnetoexcitons in Xenes, the electric field is an additional degree of freedom that can be used to tune binding energies, energy contribution from the magnetic field to the binding energies, and DMCs. Moreover, in vdWHs, we show that varying the number of hBN layers is an additional degree of freedom that can be used to tailor binding energies, energy contribution from the magnetic field to the binding energies, and DMCs. The results reported in this work on excitons in TMDCs vdWHs and in TMTCs, Xenes, and phosphorene structures are the first of their kind. They can be compared with the experimental results when they become available

Anisotropic magnetoexcitons in two-dimensional transition metal trichalcogenide semiconductors

Direct and indirect excitons in Rydberg states in transition metal trichalcogenide (TMTC) monolayers, bilayers, and van der Waals (vdW) heterostructures in an external magnetic field are studied within the framework of the effective mass approximation. Binding energies of magnetoexcitons are calculated using the Rytova-Keldysh potential for direct magnetoexcitons and both the Rytova-Keldysh and Coulomb potentials for indirect magnetoexcitons. We report the magnetic field energy contribution to the binding energies and diamagnetic coefficients for magnetoexcitons that depend strongly on the effective mass anisotropy of electrons and holes. The comparative study of TMTCs and phosphorene is given. In TiS3, TiSe3, and ZrSe3 the excitonic binding energies and diamagnetic coefficients demonstrate the same kind of anisotropy as in phosphorene. In contrast, ZrS3 has the opposite anisotropy to phosphorene. The tunability of the binding energy of direct and indirect magnetoexcitons by the external magnetic field and the possibility to control the binding energy of magnetoexcitons in vdW heterostructures by manipulation of numbers of hBN monolayers are shown

Формирование культурно-эстетического восприятия личности средствами театрального искусства

The paper addresses the problem of development of aesthetic perception in an individual by means of performing art. The potential of performing art and the special aspects of aesthetic perception development are revealed through a case study involving the primary school children. Defined is the concept of ‘aesthetic perception’, as well as the criteria and levels of its development; revealed are the psychological mechanisms of influence of performing art, being poly-artistic at its core, on the development of cultural and aesthetic perception in an individual. Described is the process of diagnosing and shaping aesthetic perception in primary school children through stage and creative activities. Delivered are the results of research on the problem reflecting the positive dynamics revealed in the experimental participants. Keywords: aesthetic perception, primary school children, means of performing art.El artículo aborda el problema del desarrollo de la percepción estética en un individuo por medio del arte escénico. El potencial del arte escénico y los aspectos especiales del desarrollo de la percepción estética se revelan a través de un estudio de caso que involucra a los niños de la escuela primaria. Definido es el concepto de "percepción estética", así como los criterios y niveles de su desarrollo; Se revelan los mecanismos psicológicos de influencia del arte escénico, que son poli- artísticos en su núcleo, en el desarrollo de la percepción cultural y estética en un individuo. Se describe el proceso de diagnóstico y configuración de la percepción estética en los niños de la escuela primaria a través de actividades escénicas y creativas. Se entregan los resultados de la investigación sobre el problema que refleja la dinámica positiva revelada en los participantes experimentales.Статья посвящена проблеме формирования эстетического восприятия личности средствами театрального искусства. Раскрыт потенциал театрального искусства, особенности формирования эстетического восприятия на примере обучающихся в начальной школе. Дано понятие «эстетическое восприятие», выявлены критерии и уровни его сформированности, психологические механизмы влияния полихудожественного по своей сути театрального искусства на процесс формирования культурно-эстетического восприятия личности. Охарактеризован процесс диагностики и формирования эстетического восприятия у обучающихся начальных классов посредством театральнотворческой деятельности. Представлены результаты исследовательской работы по проблеме, отражающие положительную динамику у испытуемых в экспериментальной группе

СОЦИОКУЛЬТУРНЫЕ И ЭСТЕТИЧЕСКИЕ АСПЕКТЫ ФОРМИРОВАНИЯ ПРОФЕССИОНАЛЬНОЙ НАПРАВЛЕННОСТИ СТУДЕНТА – БУДУЩЕГО УЧИТЕЛЯ НАЧАЛЬНОЙ ШКОЛЫ

The article is devoted to the disclosure of socio-cultural and aesthetic aspects of the formation of the professional orientation of a student – a future elementary school teacher. The authors reveal the socio-cultural and aesthetic potential of university disciplines in the personal development of a student – a future teacher. They characterize the features of the formation of the teacher’s professional orientation, the basis of which are his/her humanitarian and pedagogical culture and spirituality as the highest level of development and self-regulation of a mature personality, on which the highest human values become the main reference points of his/her life. Further, on the basis of the characteristics of the research methods, the article presents the results of the diagnostics of the formation of socio-cultural and aesthetic aspects of the professional orientation of the students of the pedagogical university – future elementary school teachers, reflecting the positive dynamics of the development of the qualities we consider in subjects in the experimental group.Статья посвящена раскрытию социокультурных и эстетических аспектов формирования профессиональной направленности студента – будущего современного учителя начальной школы. Раскрыт социокультурный и эстетический потенциал вузовских дисциплин в личностном становлении студента – будущего учителя. Охарактеризованы особенности формирования профессиональной направленности педагога, базисом которой являются его гуманитарно-педагогическая культура и духовность как высший уровень развития и саморегуляции зрелой личности, на котором основными ориентирами ее жизнедеятельности становятся высшие человеческие ценности. Далее, на основе характеристики методов исследования, в статье представлены результаты диагностики сформированности социокультурных и эстетических сторон профессиональной направленности у студентов педагогического вуза – будущих учителей начальных классов, отражающие положительную динамику развития рассматриваемых нами качеств у испытуемых в экспериментальной группе

The Price Competitive Analysis on the Public Transport Market

Import 01/09/2009Prezenční116 - Katedra marketingu a obchoduvelmi dobř

Animal waste utilization technology

The applicability of learned introduction of anaerobic digestion of animal waste will be obvious after a wide setting of afull-scale experiment and an across-the-board economic feasibility.However, yet today, basing on the domestic and abroad practice on biopowerdigesters engineering and operation,it can be argued that their use is economically advantageous than the traditional system. The obtained experience evidences thatthe cubicle housingof dairy cows is advanced. Milking operation is carried out in a special house, which ramps up milkquality, improves working conditions for milkmaids, and reduces labor costs.The problem of the animal waste impact on environment, especially on natural waters is acute. There is no summarized information about their distribution for fertilization and discharge.Not only liquid animal waste, but also silage sap causepollution. The Energy Program sets the task of widespread involvement of non-conventional energyin the country's energy balance. Biomass is of the great importance among such sources in the agro-industrial complex of the country.Anaerobicmethanoic digestion of animal waste allows evolving biogas – a valuable organic fertilizer with extra biological activityor protein-vitamin concentrates for feed supplementation.Such digestion of animal waste is an effective environmental action that provides its deodorization, reduction of soil and water pollution with repugnant substances and pathogenic microflora, atmospheric emissions (due to removal