Диэлектрические и оптические свойства кубических монокристаллов SiC, GeC и SnC: модельные оценки

Within the scope of the Harrison’s bond orbital model analytical expressions of the high- and low-frequency dielectric susceptibilities and dielectric constants, linear electrooptical coefficient, photoelastic constants and pressure dependences of the dielectric constants are obtained for the cubic carbides of the group IV elements.

Modelling of epitaxial growth of two-dimensional film

The study is devoted to the theory of epitaxial growth of two-dimensional materials (in particular, the group IV elements) and its applications in creating a virtual program for modeling this growth by the molecular beam epitaxy (MBE) method.

Rare-earth metal catalysts for high-pressure synthesis of rare diamonds

The combination of the unique properties of diamond and the prospects for its high-technology applications urges the search for new solvents–catalysts for the synthesis of diamonds with rare and unusual properties. Here we report the synthesis of diamond from melts of 15 rare-earth metals (REM) at 7.8 GPa and 1800–2100 °C. The boundary conditions for diamond crystallization and the optimal parameters for single crystal diamond synthesis are determined. Depending on the REM catalyst, diamond crystallizes in the form of cube–octahedrons, octahedrons and specific crystals bound by tetragon–trioctahedron and trigon–trioctahedron faces. The synthesized diamonds are nitrogen-free and belong to the rare type II, indicating that the rare-earth metals act as both solvent–catalysts and nitrogen getters. It is found that the REM catalysts enable synthesis of diamond doped with group IV elements with formation of impurity–vacancy color centers, promising for the emerging quantum technologies. Our study demonstrates a new field of application of rare-earth metals.

Can NOx reduction by CO react over carbon-based single-atom catalysts at low temperatures? A theoretical study

First principles studies combined with the microkinetic analysis were performed to study the reliability and reaction mechanisms of single-atom doped graphene (SADGr) materials in catalyzing NOx reduction with CO. By screening the 3d transition metals (Sc-Zn) and group-IV elements (Si and Ge), it was found that the Ti and Co doped graphene sheets (TiGr and CoGr) respectively own excellent catalytic activities in the NO/NO2-to-N2O and the N2O-to-N2 processes at low temperatures. Therefore, the TiGr/CoGr composite can be a promising catalyst in NOx reduction with CO. It was further revealed the combination of adsorption energy and electronegativity was a good descriptor to predict the activation energies. The obtained results can provide useful information for rational design of carbon-based single-atom catalysts for NOx reduction by CO at low temperatures.

Creation of pure non-crystalline diamond nanostructures via room temperature ion irradiation and subsequent thermal annealing

Carbon exhibits a remarkable range of structural forms, due to the availability of sp3, sp2 and sp1 chemical bonds. Contrarily to other group IV elements such as silicon and germanium,...

Two-dimensional XC6-enes (X=Ge, Sn, Pb) with moderate band gaps, biaxial negative Poisson's ratios, and high carrier mobility

Graphene-based analogs and derivatives provide numerous routes to achieve unconventional properties and potential applications. Particularly, two-dimensional (2D) binary materials of group-IV elements are drawing increasing interest. In this work, we...