Regularities of Electrical Conductivity of Monolayer Graphene Nanomesh with Round Holes

This paper studies graphene nanomesh with different neck width is the smallest distance between two neighboring holes. The electrical properties of graphene nanomesh with circular holes were calculated in dependence on its neck width. For the considered structures energetical characteristics including energy gap (Egap), Fermi level (Ef), and density of electron states (DOS) were found. It was established that graphene nanomesh demonstrated both metallic and semiconductor types of conductivity when the neck width was increased along the zigzag direction. In the case of increasing the neck width along armchair direction, graphene nanomesh demonstrated only a metallic type of conductivity. It was observed the anisotropy of electrical conductivity depending on the direction along which the current transfer was carried out.

Revealing quantum effects in highly conductive δ-layer systems

Thin, high-density layers of dopants in semiconductors, known as δ-layer systems, have recently attracted attention as a platform for exploration of the future quantum and classical computing when patterned in plane with atomic precision. However, there are many aspects of the conductive properties of these systems that are still unknown. Here we present an open-system quantum transport treatment to investigate the local density of electron states and the conductive properties of the δ-layer systems. A successful application of this treatment to phosphorous δ-layer in silicon both explains the origin of recently-observed shallow sub-bands and reproduces the sheet resistance values measured by different experimental groups. Further analysis reveals two main quantum-mechanical effects: 1) the existence of spatially distinct layers of free electrons with different average energies; 2) significant dependence of sheet resistance on the δ-layer thickness for a fixed sheet charge density.

Квантовый размерный эффект в сверхпроводящих пленках алюминия

High-quality aluminum films on GaAs substrates were experimentally studied. A noticeable increase in the critical temperature of the superconducting transition with a decrease in the film thickness was found. The effect is interpreted as manifestation of the quantum size effect, which affects both the density of electron states and the electron-phonon interaction.

Nanocellulose as the Main Composite Component of Electromechanical Sensors

Within the methods of the electron density functional and the ab initio pseudopotential, we have obtained the spatial distributions of the density of valence electrons, density of electron states, band gap, valence band, and charge for the cellulose-based model composite structures under mechanical influences, using authors’ program complex. It is determined that the electronic properties of composite structures based on nanocellulose can be controlled, for example, by changing the distance between the layers of composite components that happens during a mechanical compression or stretching.

Investigation on the Origin of Magnetization in Plastically Deformed NI51TI49 Alloy

The article deals with the investigation of structure and magnetic properties of plastically deformed Ni51Ti49 alloy. The magnetic hysteresis loops confirm the presence of ferromagnetic properties in the alloy. The transmission electron microscopy (TEM) detects the appearance of lenticular crystals with bending contours which indicate the large distortion of the crystal lattice. The crystal lattice curvature occurs due to the large atom displacement. As a result, icosahedral clusters with the Frank-Kasper (FK) structure can be formed. The spin-polarized density of electron states and the magnetic moments for both non-deformed (near-spherical structure) and deformed (elongated by 5% along the Z-axis) Ni7Ti5 (FK-12), Ni8Ti5 (FK-13), and Ni10Ti6 (FK-16) clusters are calculated for the explanation of possibility of magnetization appearance in Ni51Ti49 alloy. The calculations show the increase in the magnetic moments for the deformed clusters. The calculated spectra demonstrate the high density of electron states near the Fermi level which is a characteristic feature of ferromagnetic alloys.