A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer.

We calculate the current-phase relation (CPR) of a SN-S-SN Josephson junction based on a SN bilayer of variable thickness composed of a highly disordered superconductor (S) and a low-resistivity normal metal (N) with proximity-induced superconductivity. In such a junction, the N layer provides both a large concentration of phase in the weak link and good heat dissipation. We find that when the thickness of the S and the N layer and the length of the S constriction are about the superconducting coherence length the CPR is single-valued and can be close to a sinusoidal shape.

Manipulation of the Dzyaloshinskii-Moriya Interaction in Co/Pt Multilayers with Strain.

Interfacial Dzyaloshinskii-Moriya interaction (DMI) is experimentally investigated in Pt/Co/Pt multilayer films under strain. A strong variation (from 0.1 to 0.

The Structure and Chemical Composition of the Cr and Fe Pyrolytic Coatings on the MWCNTs' Surface According to NEXAFS and XPS Spectroscopy.

The paper is devoted to the structure and properties of the composite material based on multi-walled carbon nanotubes (MWCNTs) covered with pyrolytic iron and chromium. Fe/MWCNTs and Cr/MWCNTs nanocomposites have been prepared by the metal organic chemical vapor deposition (MOCVD) growth technique using iron pentacarbonyl and bis(arene)chromium compounds, respectively. Composites structures and morphologies preliminary study were performed using X-ray diffraction, scanning and transmission electron microscopy and Raman scattering.

Superconducting phase transitions in disordered NbTiN films.

Suppression of superconductivity in disordered systems is a fundamental problem of condensed matter physics. Here we investigate superconducting niobium-titanium-nitride (NbTiN) thin films grown by the atomic layer deposition (ALD) with slightly different growth process parameters. We observe a smooth crossover from the disorder-driven superconductor-normal metal transition (SMT) to the superconductor-insulator transition (SIT) via the intermediate Bose metal state detected by the low-temperature saturation of the temperature dependence of the sheet resistance.

Artificial Dense Lattices of Magnetic Skyrmions.

Multilayer Co/Pt films with perpendicular magnetic anisotropy are irradiated by focused a He ion beam to locally reduce the anisotropy value. The irradiated spots with the diameters of 100 and 200 nm are arranged in square lattices with the periods of 200 and 300 nm. The formation of nonuniform magnetic states within the spots was observed by magnetic force microscopy methods.

Optical constants of sputtered beryllium thin films determined from photoabsorption measurements in the spectral range 20.4-250 eV.

In this work, the refractive index of beryllium in the photon energy range 20.4-250 eV was experimentally determined. The initial data include measurements of the transmittance of two free-standing Be films with thicknesses of 70 nm and 152 nm, as well as reflectometric measurements of similar films on a substrate.

A Small Cationic Organo-Copper Cluster as Thermally Robust Highly Photo- and Electroluminescent Material.

Organic light-emitting diodes (OLEDs) are revolutionizing display applications. In this aspect, luminescent complexes of precious metals such as iridium, platinum, or ruthenium still playing a significant role. Emissive compounds of earth-abundant copper with equivalent performance are desired for practical, large-scale applications such as solid-state lighting and displays.

Sign-Reversing Hall Effect in Atomically Thin High-Temperature Bi_{2.1}Sr_{1.9}CaCu_{2.0}O_{8+δ} Superconductors.

We developed novel techniques to fabricate atomically thin Bi_{2.1}Sr_{1.9}CaCu_{2.

Universal First-Passage-Time Distribution of Non-Gaussian Currents.

We investigate the fluctuations of the time elapsed until the electric charge transferred through a conductor reaches a given threshold value. For this purpose, we measure the distribution of the first-passage times for the net number of electrons transferred between two metallic islands in the Coulomb blockade regime. Our experimental results are in excellent agreement with numerical calculations based on a recent theory describing the exact first-passage-time distributions for any nonequilibrium stationary Markov process.

Threshold energies of Auger recombination in HgTe/CdHgTe quantum well heterostructures with 30-70 meV bandgap.

We calculate the threshold energies of Auger recombination in the HgTe/CdHgTe quantum well heterostructures with the bandgap in the 30-70 meV range. It is shown that there is a maximum in the temperature dependence of the threshold energy for Auger process involving two electrons and a hole. For Auger process involving two holes and an electron, in which the hole is in the second valence subband in the final state, the threshold energy decreases down to zero and then increases steeply as temperature grows.

X-ray scattering by the fused silica surface etched by low-energy Ar ions.

Anomalously high x-ray scattering at a wavelength of 0.154 nm by super-polished substrates of fused silica, which were etched by the argon ions with the energy of 300 eV, is detected. The scattering intensity increases monotonically with increasing of the etching depth.

Stripe structures in phase separated magnetic oxides.

We investigate the phase separated inhomogeneous charge and spin states in magnetic oxides. In particular, we study one dimensional harmonic waves and stripe structures. We show that harmonic spin charge waves are unstable and inevitably transform into two or three dimensional structures, while the stripe structures can be stable for certain parameters.

Features of the Molecular Structure and Luminescence of Rare-Earth Metal Complexes with Perfluorinated (Benzothiazolyl)phenolate Ligands.

A set of Sc, Nd, Sm, Eu, Ho, Gd, Er, Yb complexes with perfluorinated 2-(benzothiazol-2-yl)phenolate ligands Ln(SON)(DME) were synthesized by the reactions of silylamides Ln[N(SiMe)] with phenol H(SON). The structure of the initial phenol, Sc, and Er complexes was established using X-ray analysis, which revealed that the obtained compounds are mononuclear, in contrast to the binuclear non-fluorinated analogues [Ln(SON)] synthesized earlier. All the obtained complexes, both in solid state and in tetrahydrofuran (THF) solutions, upon excitation by light with λ 395 or 405 nm show intense luminance of the ligands at 440-470 nm.

A method of z-tomography using high-aperture soft X-ray microscopy.

Multilayer normal-incidence mirrors allow the numerical aperture (NA=0.3-0.5) of a projection lens to be significantly increased in the spectral ranges of the water (λ = 2.

Theory of Magnetic Domain Phases in Ferromagnetic Superconductors.

Recently discovered superconducting P-doped EuFe_{2}As_{2} compounds reveal the situation when the superconducting critical temperature substantially exceeds the ferromagnetic transition temperature. The main mechanism of the interplay between magnetism and superconductivity occurs to be an electromagnetic one, and a short-period magnetic domain structure was observed just below Curie temperature [V. S.

Giant Water Clusters: Where Are They From?

A new mechanism for the formation and destruction of giant water clusters (ten to hundreds of micrometers) is proposed. Our earlier hypothesis was that the clusters are associates of liquid-crystal spheres (LCS), each of which is formed around a seed particle, a microcrystal of sodium chloride. In this study, we show that the ingress of LCSs into water from the surrounding air is highly likely.

Landau level spectroscopy of valence bands in HgTe quantum wells: effects of symmetry lowering.

The Landau level spectroscopy technique has been used to explore the electronic structure of the valence band in a series of p-type HgTe/HgCdTe quantum wells with both normal and inverted ordering of bands. We find that the standard axial-symmetric 4-band Kane model, which is nowadays widely applied in physics of HgTe-based topological materials, does not fully account for the complex magneto-optical response observed in our experiments-notably, for the unexpected avoided crossings of excitations and for the appearance of transitions that are electric-dipole forbidden within this model. Nevertheless, reasonable agreement with experiments is achieved when the standard model is expanded to include effects of bulk and interface inversion asymmetries.

Magnetoconductivity and Terahertz Response of a HgCdTe Epitaxial Layer.

An epitaxial layer of HgCdTe-a THz detector-was studied in magnetotransmission, magnetoconductivity and magnetophotoconductivity experiments at cryogenic temperatures. In the optical measurements, monochromatic excitation with photon frequency ranging from 0.05 THz to 2.

Radiative recombination in narrow gap HgTe/CdHgTe quantum well heterostructures for laser applications.

Radiative recombination is studied in CdHgTe/HgTe QWs with bandgap in the 40-140 meV range using four-band Kane model. Calculated radiative lifetimes agree well with the photoconductivity kinetics measurements. We show that the side maxima in the valence band hinder the radiative recombination at high carrier concentrations and discuss how to overcome this effect for the development of long-wavelength lasers.

Beryllium-Based Multilayer Mirrors and Filters for the Extreme Ultraviolet Range.

This paper presents the first results of systematic studies of beryllium as a material for multilayer mirrors (MLM) and transmission filters (TF) for the EUV spectral range. The objective for the study is the need for the increase in reflectivity and spectral resolution of MLMs for studying the Sun's corona. We investigated Mo/Be (working wavelength is 13.

Dynamical instability of the electric transport in superconductors.

We develop a nonlinear theory of the electronic transport in superconductors in the framework of the time-dependent Ginzburg-Landau (TDGL) equation. We utilize self-consistent Gaussian approximation and reveal the conditions under which the current-voltage V(I) dependence (I-V characteristics) acquires an S-shape form leading to switching instabilities. We demonstrate that in two-dimensions the emergence of such an instability is a hallmark of the Berezinskii-Kosterlitz-Thouless (BKT) transition that we have detected by transport measurements of titanium nitride (TiN) films.

Towards the indium nitride laser: obtaining infrared stimulated emission from planar monocrystalline InN structures.

The observation of a stimulated emission at interband transitions in monocrystalline n-InN layers under optical pumping is reported. The spectral position of the stimulated emission changes over a range of 1.64 to 1.

Inverse proximity effect in semiconductor Majorana nanowires.

We study the influence of the inverse proximity effect on the superconductivity nucleation in hybrid structures consisting of semiconducting nanowires placed in contact with a thin superconducting film and discuss the resulting restrictions on the operation of Majorana-based devices. A strong paramagnetic effect for electrons entering the semiconductor together with spin-orbit coupling and van Hove singularities in the electronic density of states in the wire are responsible for the suppression of superconducting correlations in the low-field domain and for the reentrant superconductivity at high magnetic fields in the topologically nontrivial regime. The growth of the critical temperature in the latter case continues up to the upper critical field destroying the pairing inside the superconducting film due to either orbital or paramagnetic mechanism.