Selective spectroscopy of tunneling transitions between the Landau levels in vertical double-gate graphene–boron nitride–graphene heterostructures

The spectral and total electron densities of states in two-dimensional FeAs clusters, which simulate iron-based superconductors, have been calculated using the generalized quantum Monte Carlo algorithm within the full two-orbital model. Spectra have been reconstructed by solving the integral equation relating the Matsubara Green’s function and spectral density by the method combining the gradient descent and Monte Carlo algorithms. The calculations have been performed for clusters with dimensions up to 10 × 10 FeAs cells. The profiles of the Fermi surface for the entire Brillouin zone have been presented in the quasiparticle approximation. Data for the total density of states near the Fermi level have been obtained. The effect of the interaction parameter, size of the cluster, and temperature on the spectrum of excitations has been studied.     

Photoinduced grafting polymerization onto the surface with the use of radiation of high-power ultraviolet light-emitting diodes

The photoinduced grafting polymerization of acrylic acid onto the surface of a polypropylene film under the action of radiation with a wavelength of 365 nm and an intensity of 8–193 mW/cm² emitted by high-power UV light-emitting diodes is studied. Grafting is performed from a thin layer of the aqueous solution of the monomer onto the surface containing a photoinitiator (benzophenone) deposited from a solution in a volatile solvent. The amount of graft polymer is determined with the use of ATR FTIR spectroscopy. At an intensity of UV radiation of 193 mW/cm², the time of attainment of grafting-polymerization saturation is decreased by a factor of 6 relative to this time at an intensity of 8 mW/cm², typical for emitters based on mercury lamps. The rate of grafting polymerization in the studied UV-radiation-intensity range grows in proportion to the square root of intensity.     

Nonforward color-octet kernel of the Balitsky-Fadin-Kuraev-Lipatov equation

The contribution to the kernel of the nonforward Balitsky-Fadin-Kuraev-Lipatov equation from two-gluon production is calculated for the case of the antisymmetric color-octet state of two Reggeized gluons in the t channel. The one-gluon contribution to the kernel in the one-loop approximation is also obtained by using the one-loop expression for the effective vertex of the one-gluon production in Reggeon-Reggeon collisions. An explicit form of the total kernel is presented.     

Transfer measurements for the Ti+Ni systems at near barrier energies

Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2⁺ and 3⁻ states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for ^46,48Ti+⁶¹Ni systems. The present paper gives the results of these studies.     

Electronic properties of A<Subscript>2</Subscript>B<Subscript>6</Subscript> quantum dots incorporated into Langmuir–Blodgett films

An experimental and theoretical study is performed for features of the electronic spectrum of CdSe/CdS/ZnS quantum dots incorporated into Langmuir–Blodgett films. Analysis of the investigated samples assesses the state of the first three levels of the electron spectrum for a quantum object. Good qualitative and quantitative agreement is achieved between the experimental results and theoretical estimates. It is shown that the mechanism of the observed field emission current through a quantum dot is described satisfactorily by the Morgulis–Stratton theory under the considered experimental conditions.     

Observation of Spin and Valley Splitting of Landau Levels under Magnetic Tunneling in Graphene/Boron Nitride/Graphene Structures

Resonance magnetic tunneling in heterostructures formed by graphene single sheets separated by a hexagonal boron nitride barrier and bounded by two gates has been investigated in a strong magnetic field, which has allowed observing transitions between spin- and valley-split Landau levels with various indices belonging to different graphene sheets. An unexpected increase with the temperature in the interlayer tunneling conductance owing to transitions between the Landau levels in strong magnetic fields cannot be explained by existing theories.     

CVD graphene vs. highly ordered pyrolytic graphite for use in electroanalytical sensing

We explore and contrast the electroanalytical performance of a commercially available CVD grown graphene electrode with that of edge- and basal-plane pyrolytic graphite electrodes constructed from highly ordered pyrolytic graphite for the sensing of biologically important analytes, namely β-nicotinamide adenine dinucleotide (NADH) and uric acid (UA). We demonstrate that for the analytes studied here, in the best case, the electroanalytical performance of the CVD-graphene mimics that of edge plane pyrolytic graphite, suggesting no significant advantage of utilising CVD-graphene in this context.     

Extremum problems for entire functions of exponential spherical type

We consider extremum problems for entire functions of exponential spherical type related to important extremum problems on the optimal point (the Chernykh point) in the sharp jackson inequality in the spaceL ₂(ℝ ⁿ ) and the connection between codes and designs on the torusT ⁿ . Translated fromMatematicheskie Zametki, Vol. 68, No. 2, pp. 179–187, August, 2000.