Tailoring exchange interactions in engineered nanostructures: Ab initio study

We present a novel approach to spin manipulation in atomic-scale nanostructures. Our ab initio calculations clearly demonstrate that it is possible to tune magnetic properties of sub-nanometer structures by adjusting the geometry of the system. By the example of two surface-based systems we demonstrate that (i) the magnetic moment of a single adatom coupled to a buried magnetic Co layer can be stabilized in either a ferromagnetic or an antiferromagnetic configuration depending on the spacer thickness. It is found that a buried Co layer has a profound effect on the exchange interaction between two magnetic impurities on the surface. (ii) The exchange interaction between magnetic adatoms can be manipulated by introducing artificial nonmagnetic Cu chains to link them.Comment: 4 pages, submitted to PR

Size-dependent Surface States on Strained Cobalt Nanoislands on Cu(111)

Low-temperature scanning tunneling spectroscopy over Co nanoislands on Cu(111) showed that the surface states of the islands vary with their size. Occupied states exhibit a sizeable downward energy shift as the island size decreases. The position of the occupied states also significantly changes across the islands. Atomic-scale simulations and ab inito calculations demonstrate that the driving force for the observed shift is related to size-dependent mesoscopic relaxations in the nanoislands.Comment: 4 pages, 4 figure

Oppositions and Antinomies of Modern Educational Reality

The article reveals some unresolved issues concerning the processes of planning, organizing, conducting and evaluating university education in modern conditions. The purpose of the study is to clarify what oppositions are currently being maintained, and what needs to be done to address problematic situations. Among the oppositions identified by the author, there are oppositions between the standardization and unification of education, which are opposed by the autonomy of universities and the individualization of the learning process; between thread-group organization of educational process, characteristic of the traditional system of higher education, and building of individual educational trajectory; between pedagogue-centered and student-centered paradigms of higher education; between the traditional system of education (teaching) and electronic learning (e-learning), between the old system of assessing students based on the exams in specific disciplines, and the need to determine the level of formation of competences; between academic and scientific models ofpostgraduate school.The following research methods were implemented: a theoretical method (analysis of scientific literature, legislative and normative documents, teaching materials, internal local acts relating to the organization of the educational activities of the University), interpretation (comprehensive and systematic study of the object of study, comparing different objects of study among themselves, summarizing their theoretical and practical experience, etc.). In the study, based on the identified oppositions in the organization of the educational process at the University - standardization and unification of education, the conclusions were made about the need for thorough and comprehensive analysis of the existing management system of higher education and suggestions for its improvement and bringing into line not only with the requirements of legislative and normative documents regulating activity of the Russian universities, but also taking into account the interests of all the stakeholders interested in the learning outcomes and the preparation of competitive specialists

Tailoring exchange interactions in engineered nanostructures: Ab initio study

We present a novel approach to spin manipulation in atomic-scale nanostructures. Our ab initio calculations clearly demonstrate that it is possible to tune magnetic properties of sub-nanometer structures by adjusting the geometry of the system. By the example of two surface-based systems we demonstrate that (i) the magnetic moment of a single adatom coupled to a buried magnetic Co layer can be stabilized in either a ferromagnetic or an antiferromagnetic configuration depending on the spacer thickness. It is found that a buried Co layer has a profound effect on the exchange interaction between two magnetic impurities on the surface. (ii) The exchange interaction between magnetic adatoms can be manipulated by introducing artificial nonmagnetic Cu chains to link them.Comment: 4 pages, submitted to PR

Electroweak symmetry breaking and cold dark matter from strongly interacting hidden sector

We consider a hidden sector with a vectorlike confining gauge theory like QCD with $N_{h,c}$ colors and $N_{h,f}$ light quarks ${\cal Q}_h$ in the hidden sector. Then a scale $\Lambda_H$ would be generated by dimensional transmutation, and chiral symmetry breaking occurs in the hidden sector. This scale $\Lambda_H$ can play a role of the SM Higgs mass parameter, triggering electroweak symmetry breaking (EWSB). Furthermore the lightest mesons in the hidden sector is stable by flavor conservation of the hidden sector strong interaction, and could be a good cold dark matter (CDM). We study collider phenomenology, and relic density and direct detection rates of the CDM of this model.Comment: The version which appeared in Phys. Lett.

Spectator Effects in the Decay B -> K \gamma \gamma

We report the results of the first computation related to the study of the spectator effects in the rare decay mode $B\to K \gamma \gamma$ within the framework of Standard Model. It is found that the account of these effects results in the enhancement factor for the short-distance reducible contribution to the branching ratio.Comment: 5 pages, 5 figures, RevTeX