Nucleation of Ge quantum dots on the Si(001) surface

A direct observation of nucleation of Ge hut clusters formed by ultrahigh vacuum molecular beam epitaxy is reported for the first time. The nuclei of the pyramidal and wedge-like clusters have been observed on the wetting layer blocks and found to have different structures. The growth of the clusters of both species goes on following different scenarios: Formation of the second atomic layer of the wedge-like cluster results in rearrangement of its first layer. Its ridge structure does not replicate the structure of the nucleus. The pyramidal cluster grows without phase transitions. The structure of its vertex copies the structure of the nucleus. The wedge-like clusters contain point defects on the triangular faces and have preferential directions of growth along the ridges. The derived structure of the {105} facet corresponds to the PD model. The critical epinucleation phenomenon may be responsible for hut formation.Comment: 6 pages, 6 figures; Fig. 4e has been improved; additional explanations have been added. To appear in Phys. Rev.

Finding mesoscopic communities in sparse networks

We suggest a fast method to find possibly overlapping network communities of a desired size and link density. Our method is a natural generalization of the finite-$T$ superparamegnetic Potts clustering introduced by Blatt, Wiseman, and Domany (Phys. Rev. Lett. v.76, 3251 (1996) and the recently suggested by Reichard and Bornholdt (Phys. Rev. Lett. v.93, 21870 (2004)) annealing of Potts model with global antiferromagnetic term. Similarly to both preceding works, the proposed generalization is based on ordering of ferromagnetic Potts model; the novelty of the proposed approach lies in the adjustable dependence of the antiferromagnetic term on the population of each Potts state, which interpolates between the two previously considered cases. This adjustability allows to empirically tune the algorithm to detect the maximum number of communities of the given size and link density. We illustrate the method by detecting protein complexes in high-throughput protein binding networks.Comment: 8 pages, 2 figure, typos corrected, 1 figure adde

The forming factors of high values of superconducting transition temperature Tc in 3d-Transition metal compounds. I. The main groups of known superconductors

The review of modern known groups of superconductors is presented. The main classification rule is the type of chemical bonding. The factors of forming superconducting transition temperature are impurities and the external pressure. © 2013 Elmira Yuryeva and Anatoliy Yuryev

The forming factors of high values of superconducting transition temperature Tc in 3d-Transition metal compounds. II. Empirical and theoretical equipments for receiving the values of superconducting transition temperature Tc

The review of empirical and theoretical studies of the superconducting transition temperature is presented. It is shown that correlation between the parameters of chemical bonds and the value of the superconducting transition temperature is realized. © 2013 Elmira Yuryeva and Anatoliy Yuryev

Employee engagement: review of tools

В статье рассмотрена сущность такого инструмента кадровой политики, как вовлеченность персонала. На основе проведенного анализа отечественной и зарубежной литературы были представлены основные трактовки данного термина, обозначены ключевые подходы к анализу вовлеченности персонала, представлен авторский вклад в вопросе повышения уровня вовлеченности в организации.This paper considers employee engagement as the tool of personnel policies. Based on the Russian and foreign literature analysis, the basic interpretation of this term was presented. Key approaches to the analysis of employee engagement were outlined, the author's contribution to increase the employee engagement was shown

Influence of Photoexcitation Depth on Luminescence Spectra of Bulk GaAs Single Crystals and Defect Structure Characterization

The results of investigation of bulk GaAs photoluminescence are presented taken from near-surface layers of different thicknesses using for excitation the light with the wavelengths which are close but some greater than the excitonic absorption resonances (so-called bulk photoexcitation). Only the excitonic and band-edge luminescence is seen under the interband excitation, while under the bulk excitation, the spectra are much more informative. The interband excited spectra of all the samples investigated in the present work are practically identical, whereas the bulk excited PL spectra are different for different samples and excitation depths and provide the information on the deep-level point defect composition of the bulk materials.Comment: Aalborg Summer School on Nonlinear Optics, Aalborg, Denmark, 7-12 August 199