Metallic Type Of Conductivity Research Articles

Structure, bonding, and properties of RCr6Ge6 intermetallics (R[dbnd]Gd–Lu)

We report the discovery and characterization of three novel ternary compounds: TmCr6Ge6, YbCr6Ge6, and LuCr6Ge6, which complete the series of RCr6Ge6 intermetallics with kagome lattice. Energy dispersive X-ray analysis revealed the off-stoichiometric composition of RCr6Ge6 (RGd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). The powder XRD analysis with subsequent Rietveld refinement showed that investigated compounds crystallize in the SmMn6Sn6 structure type (space group P6/mmm), a disordered variant of the MgFe6Ge6-type, with a small number of vacancies at the rare earth (1a) and germanium (2e) sites and two additional 1b and 2e sites partially occupied by additional rare earth and germanium atoms, respectively. A tendency to structure ordering is observed with decreasing rare earth ionic radii. Electrical resistivity measurements indicate a metallic conductivity type for all studied compounds. Magnetic characterization reveals paramagnetic behavior for TmCr6Ge6 and LuCr6Ge6, respectively, and suggests YbCr6Ge6 as a ferrimagnetic material. The DFT modeling of RCr6Ge6 shows a distinct high electron localization between Ge1 atoms, corresponding to strong covalent bonding. The calculated enthalpies of formation range from −18.56 kJ/mol for Gd to −19.60 for Tm compounds, while the distribution of the density of electronic states (DOS) confirms the metallic type of conductivity for all the series. The calculated elastic properties show brittle behavior and a high hardness level for the whole series. DFT modeling allowed us to reveal mechanisms of RCr6Ge6 formation and the origin of disorder in their crystal structure.

High figure-of-merit of single-walled carbon nanotubes films with metallic type conduction

Carbon nanotubes are promising candidates for thermoelectric power generation because of their one-dimensionality mediated high Seebeck coefficient, high electrical conductivity with added advantages of flexibility, light weight, and scalability. We report the temperature-dependent thermoelectric properties of single-walled carbon nanotube (SWCNTs) films. The SWCNTs films exhibit p-type metallic conduction with high Seebeck coefficient (∼69.5 μVK−1) and moderate electrical conductivity (∼76 Scm−1). The films exhibit low thermal conductivity (∼0.1 Wm−1 K−1) due to phonon scattering at the interjunction region. The synergetic combination of thermoelectric properties resulted in a high figure-of-merit of ∼0.11 at 305 K. A flexible thermoelectric generator based on SWCNTs films mounted on a curved hot surface exhibited an output of 17 mV and 54 μA under a small temperature gradient of 10 K. The present work provides possible avenues for developing wearable SWCNTs based thermoelectric power generation modules for harvesting body heat.

Investigation of a 2D Metallic Selenide for Supercapacitative Applications

The study investigates the suitability of a 2D metallic selenide material for use in supercapacitors, which are rapidly gaining recognition as a viable energy storage solution. While supercapacitors are highly efficient at charging and discharging, their lower energy density is a limiting factor. This research focuses on identifying new materials that can enhance the energy density of supercapacitors while maintaining their rapid charging capabilities. The study examines CrSe2, a promising chalcogenide material that has recently been suggested for use in hybrid composite systems. The research shows that CrSe2 can be made in bulk quantities and exhibits high stability in certain electrolytes. The electrochemical properties of CrSe2 are measured for the first time and found to be consistent with an electric double-layer capacitance. Additionally, the material demonstrates a high specific capacitance, indicating potential for use in supercapacitive applications. The study concludes that the metallic-type conductivity of CrSe2 could be responsible for its superior performance over high surface area carbon black samples.

Charge invertible nanowires [Ni5Bi5.6]x (x = 1+, 0, 1−): Infinite columns [Ni5Bi5.6]− in a novel quasi-one-dimensional compound KNi5Bi5.6

A novel quasi-one-dimensional (Q1D) compound KNi5Bi5.6 has been synthesized and its crystal structure has been determined by X-ray crystallography. The structure contains double-walled anionic nanowires [Ni5Bi5.6]− separated by potassium cations. KNi5Bi5.6 forms a new series of compounds together with previously reported Bi5.6Ni5I and Bi28Ni25 featuring [Ni5Bi5.6]x (x = 1+, 0, 1−) nanowires for which the charge can be cationic, neutral or anionic without appreciably affecting the structure and composition. This unique characteristic provides a new platform to investigate charge invertible Q1D transition metal systems. Resistivity measurement of KNi5Bi5.6 reveals a metallic type of conductivity. Magnetic susceptibility obeys a modified Curie-Weiss behavior with a small average effective magnetic moment of Ni and shows a weak magnetic anisotropy.

Effect of a Discontinuous Ag Layer on Optical and Electrical Properties of ZnO/Ag/ZnOStructures

ZnO/Ag/ZnO nanolaminate structures were deposited by consecutive RF sputtering at room temperature.The optical transparency, sheet resistance, and figure of merit are determined in relation to the deposition time of Ag and to the film thickness of the ZnO top layer. An improved transmittance has been found in the visible spectral range of the ZnO/Ag/ZnO structure compared to ZnO multilayers without Ag. High transmittance of 98% at 550 nm, sheet resistance of 8 Ω/sq, and figure of merit (FOM) of 111.01 × 10−3 Ω−1are achieved for an optimized ZnO/Ag/ZnO nanolaminate structure. It is suggested that the good optical and electrical properties are due to the deposition of the discontinuous Ag layer. The electrical metallic type conductivity is caused by planar located silver metal granules. The deposition of a discrete layer of Ag nano-granules is confirmed by atomic force microscopy (AFM) and cross-section high-resolution transmission electron microscopy (HRTEM) observations.

Nanostructured Iridium Oxide: State of the Art

Iridium Oxide (IrO2) is a metal oxide with a rutile crystalline structure, analogous to the TiO2 rutile polymorph. Unlike other oxides of transition metals, IrO2 shows a metallic type conductivity and displays a low surface work function. IrO2 is also characterized by a high chemical stability. These highly desirable properties make IrO2 a rightful candidate for specific applications. Furthermore, IrO2 can be synthesized in the form of a wide variety of nanostructures ranging from nanopowder, nanosheets, nanotubes, nanorods, nanowires, and nanoporous thin films. IrO2 nanostructuration, which allows its attractive intrinsic properties to be enhanced, can therefore be exploited according to the pursued application. Indeed, IrO2 nanostructures have shown utility in fields that span from electrocatalysis, electrochromic devices, sensors, fuel cell and supercapacitors. After a brief description of the IrO2 structure and properties, the present review will describe the main employed synthetic methodologies that are followed to prepare selectively the various types of nanostructures, highlighting in each case the advantages brought by the nanostructuration illustrating their performances and applications.

Magnetic, Magnetocaloric, and Electric Transport Properties of Sr2FeMoO6–δ Double Perovskites with Different Degrees of Superstructural Ordering

Pressed strontium ferromolybdate (Sr2FeMoO6−δ) pellets with different oxygen indices δ and degrees of superstructural ordering (SO) are synthesized by solid‐phase and citrate‐gel methods to study magnetic and electric transport behaviors of this compound. The crystalline structure of the samples is found to demonstrate ordering of the Fe and Mo cations, which increases with increase in δ. The saturation magnetization and the Curie temperature of the samples correlate with the degree of SO. The Banerjee criterion indicates that the compounds studied undergo a second‐order phase transition. The temperature dependence of the isothermal change of entropy in magnetic field is determined by the Maxwell approach. The additional low‐temperature annealing is found to change the sample conductivity of metallic type for semiconducting one and significantly increases the magnetoresistance due to intergrain electron tunneling.

Electrical transport properties of R1.9Cu9.2Sn2.8 compounds

Electrical transport properties of the R 1.9 Cu 9.2 Sn 2.8 (R = Y, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) compounds with the Dy 1.9 Cu 9.2 Sn 2.8 structure type (space group P 6 3 / mmc ) were studied. Polycrystalline samples were prepared by arc melting of the stoichiometric amounts of the constituent elements (nominal purities: rare earth metals − 99.9 wt. %, Cu − 99.99 wt. %, Sn − 99.999 wt. %) on a water-cooled copper hearth under a protective Ti-gettered argon atmosphere. Subsequently the buttons were annealed at 1 070 K for 720 h in evacuated silica tubes, followed by quenching in cold water. Quality of the prepared samples was tested by X-ray powder diffraction (diffractometer DRON-2.0M, Fe K α radiation) and Scanning Electron Microscopy (REMMA 102-02 electron microscope equipped with an energy-dispersive spectroscopy X-ray analyser). XRPD data were collected in the transmission mode on a STOE STADI P diffractometer (Cu K α 1 radiation). The temperature dependencies of electrical resistivity ( r ( T )) of R 1.9 Cu 9.2 Sn 2.8 stannides were measured employing two-probe method on millimeter-scale, well-shaped pieces cut by spark erosion from the polycrystalline samples in the temperature range 4.2-300 K (R = Ce, Gd, Tb, Dy, Ho, Er, Tm, Yb) and 11-300 K (R = Y, Sm, Lu). Electrical resistivity measurements showed that the resistivity values of the all studied compounds increase with temperature indicating metallic type of conductivity. For Y 1.9 Cu 9.2 Sn 2.8 and Lu 1.9 Cu 9.2 Sn 2.8 stannides, which contain nonmagnetic elements Y and Lu, the absence of transition on the r ( T ) dependences at low temperatures is consistent with the Pauli paramagnetism of compounds. The temperature dependence of the resistivity of Yb 1.9 Cu 9.2 Sn 2.8 compound is almost linear at high temperatures, at low temperature part there is a slight increase in resistivity, which is characteristic of Kondo systems. Change of the resistivity caused by magnetic ordering was not observed in the studied temperature interval for the R 1.9 Cu 9.2 Sn 2.8 compounds where R are Gd, Tb, Ho, Er. The slope change of the resistivity at low temperature part of r ( T ) dependencies for the R 1.9 Cu 9.2 Sn 2.8 compounds with R=Ce, Dy, Tm is associated with their magnetic ordering. Keywords : intermetallics, electrical resistivity, X-ray analysis, crystal structure.

Металлическая проводимость в слоях нанопористого кремния на поверхности ЦТС-керамики

Nanoporous silicon and ceramics based on lead zirconate titanate (PZT-ceramics) have unique properties in themselves. It is shown that their mechanochemical interaction makes it possible to create compositions with a metallic type of conductivity. The formation of conductive paths occurs when silicon particles wedged into microcracks, creating unique highly sensitive layers of piezoceramic compounds, incl. intercalates. Silicon atoms embedded deform the elementary cells of crystals and redistribute charges in them. The connection with the lattice is formed due to the transition of electrons to the boundary layers or the space between them. In the transition layers at T < 260 K, chains with electrical conductivity of the metallic type appear, shunting the piezodielectric.

Physical properties of {Ti,Zr,Hf}2Ni2Sn compounds.

Physical properties, i.e. electrical resistivity (4.2-800 K), Seebeck coefficient (300-800 K), specific heat (2-110 K), Vickers hardness and elastic moduli (RT), have been defined for single-phase compounds with slightly nonstoichiometric compositions: Ti2.13Ni2Sn0.87, Zr2.025Ni2Sn0.975, and Hf2.055Ni2Sn0.945. From X-ray single crystal and TEM analyses, Ti2+xNi2Sn1-x, x ∼ 0.13(1), is isotypic with the U2Pt2Sn-type (space group P42/mnm, ternary ordered version of the Zr3Al2-type), also adopted by the homologous compounds with Zr and Hf. For all three polycrystalline compounds (relative densities >95%) the electrical resistivity of the samples is metallic-like with dominant scattering from static defects mainly conditioned by off-stoichiometry. Analyses of the specific heat curves Cpvs. T and Cp/T vs. T2 reveal Sommerfeld coefficients of γTi2Ni2Sn = 14.3(3) mJ mol-1 K-2, γZr2Ni2Sn = 10(1) mJ mol-1 K-2, γHf2Ni2Sn = 9.1(5) mJ mol-1 K-2 and low-temperature Debye-temperatures: θLTD = 373(7)K, 357(14)K and 318(10)K. Einstein temperatures were in the range of 130-155 K. Rather low Seebeck coefficients (<15 μV K-1), power factors (pf < 0.07 mW mK-2) and an estimated thermal conductivity of λ < 148 mW cm-1 K-1 yield thermoelectric figures of merit ZT < 0.007 at ∼800 K. Whereas for polycrystalline Zr2Ni2Sn elastic properties were determined by resonant ultrasound spectroscopy (RUS): E = 171 GPa, ν = 0.31, G = 65.5 GPa, and B = 147 GPa, the accelerated mechanical property mapping (XPM) mode was used to map the hardness and elastic moduli of T2Ni2Sn. Above 180 K, Zr2Ni2Sn reveals a quasi-linear expansion with CTE = 15.4 × 10-6 K-1. The calculated density of states is similar for all three compounds and confirms a metallic type of conductivity. The isosurface of elf shows a spherical shape for Ti/Zr/Hf atoms and indicates their ionic character, while the [Ni2Sn]n- sublattice reflects localizations around the Ni and Sn atoms with a large somewhat diffuse charge density between the closest Ni atoms.

Investigation of Polyvinyl Alcohol-CuS Compound with Metal-Like Conductivity

PVA-CuS compound produced from hybrid interpolymeric polyvinyl alcohol (PVA)-CuCl2 complex through solid state sulfurization was investigated by means of X-ray diffraction, UV-Vis and Raman spectroscopy, and direct current measurements. It is claimed that CuS in this compound has one-dimensional structure. This result is achieved by using a precursor technique based on diffusion limitation at solid state synthesis, so that the structure of initial reagents is inherited by reaction products. The produced material is determined to possess metal-type conductivity and thermopower in the vicinity of room temperature. Keywords: hybrid interpolymeric complexes, polyvinyl alcohol, CuS, inorganic polymers, one-dimensional structures, electrical properties.

New van der Waals Heterostructures Based on Borophene and Rhenium Sulfide/Selenide for Photovoltaics: An Ab Initio Study

One of the urgent tasks of modern materials science is the search for new materials with improved optoelectronic properties for various applications of optoelectronics and photovoltaics. In this paper, using ab initio methods, we investigate the possibility of forming new types of van der Waals heterostructures based on monolayers of triangulated borophene, and monolayers of rhenium sulfide (ReS), and rhenium selenide (ReSe2), and predict their optoelectronic properties. Energy stable atomic configurations of borophene/ReS2 and borophene/ReSe2 van der Waals heterostructures were obtained using density functional theory (DFT) calculations in the Siesta software package. The results of calculating the density of electronic states of the obtained supercells showed that the proposed types of heterostructures are characterized by a metallic type of conductivity. Based on the calculated optical absorption and photocurrent spectra in the wavelength range of 200 to 2000 nm, it is found that borophene/ReS2 and borophene/ReSe2 heterostructures demonstrate a high absorption coefficient in the near- and far-UV(ultraviolet) ranges, as well as the presence of high-intensity photocurrent peaks in the visible range of electromagnetic radiation. Based on the obtained data of ab initio calculations, it is predicted that the proposed borophene/ReS2 and borophene/ReSe2 heterostructures can be promising materials for UV detectors and photosensitive materials for generating charge carriers upon absorption of light.

Negative permittivity behavior in carbon fibre/silicon nitride ceramic composites prepared by spark plasma sintering

Carbon/ceramic composites with adjustable electrical properties can be promising candidates for electromagnetic metamaterials with negative permittivity. Herein, silicon nitride (Si3N4) ceramic composites incorporated with carbon fibres (CFs) were prepared via spark plasma sintering. The fibres were randomly distributed in the ceramic matrixes, and their amounts had a great influence on the microstructure, electrical conductivity, dielectric behaviour, and impedance response of the CF/Si3N4 composites. As the CF content was low, the ceramics with isolated CFs showed a dielectric type of conductivity, along with a capacitive character and positive permittivity. When the CFs were more sufficient to contact or overlap each other in the ceramics, the formation of CF networks endowed the ceramics with a metallic type of conductivity and inductive character. A plasma-type negative permittivity behaviour was observed in these ceramics and was imputed to the low-frequency plasmonic state of free electrons in the formed CF networks. The Drude model was applied to make a precise description of the negative permittivity behaviour. As the CF content increased, the plasma frequency (negative-positive transformation frequency of permittivity) of the ceramics shifted to a higher frequency, and their absolute magnitudes of negative permittivity also increased. Furthermore, equivalent circuit models were utilized to interpret the impedance response of the ceramics, which demonstrated that the negative permittivity was linked to the inductive character. This work provides support for developing ceramic-based metamaterials with tunable negative permittivity that is desirable for many applications.

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.

Analysis of La4Ni3O10±δ-BaCe0.9Y0.1O3-δ Composite Cathodes for Proton Ceramic Fuel Cells

Layered Ruddlesden-Popper (RP) lanthanide nickelates, Lnn+1NinO3n+1 (Ln = La, Pr, and Nd; n = 1, 2, and 3) have generated great interest as potential cathodes for proton conducting fuel cells (PCFCs). The high-order phase (n = 3) is especially intriguing, as it possesses the property of a high and metallic-type electronic conductivity that persists to low temperatures. To provide the additional requirement of high ionic conductivity, a composite electrode is here suggested, formed by a combination of La4Ni3O10±δ with the proton conducting phase BaCe0.9Y0.1O3-δ (40 vol%). Electrochemical impedance spectroscopy (EIS) is used to analyse this composite electrode in both wet (pH2O ~ 10−2 atm) and low humidity (pH2O ~ 10−5 atm) conditions in an O2 atmosphere (400–550 °C). An extended analysis that first tests the stability of the impedance data through Kramers-Kronig and Bayesian Hilbert transform relations is outlined, that is subsequently complemented with the distribution function of relaxation times (DFRTs) methodology. In a final step, correction of the impedance data against the short-circuiting contribution from the electrolyte substrate is also performed. This work offers a detailed assessment of the La4Ni3O10±δ-BaCe0.9Y0.1O3-δ composite cathode, while providing a robust analysis methodology for other researchers working on the development of electrodes for PCFCs.

Electrical conductivity of MoS2 thin films and graphite under continuous injection to protons

The electrical conductivity of thin films of MoS2 and graphite has been studied under conditions of continuous injection of low-energy protons (∼ 1-4 keV). The effect of a sharp increase (by 3-4 orders of magnitude) in the electrical conductivity of substances with a layered structure (MoS2 and graphite) at T ∼ 293 K has been established. The observed effect increases (from 2 to 10 times) as the temperature decreases from room temperature to liquid nitrogen temperature (T ∼ 77 K) and with increasing number of protons injected into the sample. The established temperature variation of electrical resistance is typical for materials with a metallic type of conductivity. It is shown that a thin surface layer, onto which protons penetrate, is responsible for the change in the electrical conductivity of MoS2 and graphite films.

FEATURES OF SIMULATION OF CHARACTERISTICS OF THERMOMETRIC MATERIAL Lu1-xZrxNiSb

The results of modeling the thermometric characteristics of the semiconductor solid solution Lu1-xZrxNiSb, which is a promising thermometric material for the manufacture of sensitive elements of thermoelectric and electro resistive thermocouples, are presented. Modeling of the electronic structure of Lu1-xZrxNiSb was performed by the Korringa-Kohn-Rostoker (KKR) method in the approximation of coherent potential and local density and by the full-potential method of linearized plane waves (FLAPW). KKR simulations were performed using the AkaiKKR software package in the local density approximation for the exchangecorrelation potential with parameterization Moruzzi, Janak, Williams in the semi-relativistic one taking into account the spin-orbit interaction. The implementation of the method in the Elk software package was used to perform FLAPW calculations. To check the limits of the existence of the thermometric material Lu1-xZrxNiSb, both methods were used to calculate the change in the values of the period of the unit cell a(x) in the range x=0–1.0. It is shown that there is an agreement between the change in the values of a(x) Lu1-xZrxNiSb calculated by the FLAPW method and the results of experimental studies. The obtained result indicates higher accuracy of modeling of structural parameters Lu1-xZrxNiSb by the FLAPW method in comparison with the KKR method. To study the possibility of obtaining thermometric material Lu1-xZrxNiSb and to establish the limits of its existence in the form of a continuous solid solution, modeling of thermodynamic characteristics in the approximation of harmonic oscillations of atoms within the theory of DFT density functional for a hypothetical solid solution Lu1-xZrxNiSb, x=0–1.0. The change in the values of the enthalpy of mixing ΔH and the total energy E Lu1-xZrxNiSb, x=0–1.0, allows us to state that the thermometric material exists in the form of a solid substitution solution in the concentration range x=0–0.20, stratification occurs (spinoidal phase decay) and thermometric material does not exist. To understand the mechanisms of electrical conductivity of the thermometric material Lu1-xZrxNiSb, the methods of entry of impurity Zr atoms into the matrix of the basic semiconductor p-LuNiSb and their occupation of different crystallographic positions, as well as the presence of vacancies in them, were investigated. For this purpose, its electronic structure was modeled for different variants of the spatial arrangement of atoms and the presence of vacancies in crystallographic positions. It is shown that the most acceptable results of experimental studies are the model of the electronic structure of p-LuNiSb, which assumes the presence of vacancies in the crystallographic positions of 4a Lu atoms (~0.005) and 4c Ni atoms (~0.04). In this model of the spatial arrangement of atoms and the presence of vacancies at positions 4a and 4c, the LuNiSb compound is a semiconductor of the hole-type conductivity, in which the Fermi level eF is located near the level of the valence band eV. The kinetic characteristics of the semiconductor thermometric material Lu1-xZrxNiSb, in particular, the temperature dependences of the resistivity ρ(T,x) and the thermopower coefficient α(T,x) are modeled. It is established that at the lowest concentrations of impurity atoms Zr the Fermi level eF Lu1-xZrxNiSb passes from the bandgap to the conduction band eС. This is indicated by the negative values of the thermopower coefficient α(T,x) and the metallic conductivity type Lu1-xZrxNiSb. This changes the type of main current carriers from holes to electrons.

Effect of the Niobium Doping Concentration on the Charge Storage Mechanism of Mesoporous Anatase Beads as an Anode for High-Rate Li-Ion Batteries

A promising strategy to improve the rate performance of Li-ion batteries is to enhance and facilitate the insertion of Li ions into nanostructured oxides like TiO2. In this work, we present a systematic study of pentavalent-doped anatase TiO2 materials for third-generation high-rate Li-ion batteries. Mesoporous niobium-doped anatase beads (Nb-doped TiO2) with different Nb5+ doping (n-type) concentrations (0.1, 1.0, and 10% at.) were synthesized via an improved template approach followed by hydrothermal treatment. The formation of intrinsic n-type defects and oxygen vacancies under RT conditions gives rise to a metallic-type conduction due to a shift of the Fermi energy level. The increase in the metallic character, confirmed by electrochemical impedance spectroscopy, enhances the performance of the anatase bead electrodes in terms of rate capability and provides higher capacities both at low and fast charging rates. The experimental data were supported by density functional theory (DFT) calculations showing how a different n-type doping can be correlated to the same electrochemical effect on the final device. The Nb-doped TiO2 electrode materials exhibit an improved cycling stability at all the doping concentrations by overcoming the capacity fade shown in the case of pure TiO2 beads. The 0.1% Nb-doped TiO2-based electrodes exhibit the highest reversible capacities of 180 mAh g–1 at 1C (330 mA g–1) after 500 cycles and 110 mAh g–1 at 10C (3300 mA g–1) after 1000 cycles. Our experimental and computational results highlight the possibility of using n-type doped TiO2 materials as anodes in high-rate Li-ion batteries.

Carbon-Nanotube Nanomesh Films with X-Shaped Junctions for Electronic and Photovoltaic Applications

The atomic structure and electronic and optoelectronic properties of nanomesh films made of carbon nanotubes with seamless cross-like X junctions are investigated. It is established that the topology of the arrangement of nonhexagonal elements in the contract region of nanotubes determines the energy stability of the atomic structure. It is revealed that the film pore sizes determine the conductivity type. The film is characterized by metal-type conductivity at the smallest pore sizes; as the gap in the band structure increases with an increase in the pore size, the film becomes semiconducting. Films with a minimal gap size have high photovoltaic characteristics. The photocurrent for the considered film models can reach 2.4 mA cm–2 under atmospheric conditions and 3.25 mA cm–2 outside the atmosphere. The presence of a gap in the band structure makes nanomesh films promising for nanoelectronics and optoelectronics.

Multiband effect in elastoresistance of Fe(Se,Te)

We have investigated the elastoresistance of two Tex () compounds that have a close chemical composition but differ significantly in electronic properties. The first compound has a negative temperature coefficient of resistance and does not show any phase transitions other than a superconducting one. The elastoresistance of this compound approximately follows the law which is a special case of the Curie-Weiss law, which is usually observed for Fe(Se,S) with metallic conductivity. The second compound has a metallic type of conductivity and, in addition to the superconducting transition, there is also a phase transition at a temperature of about 30 K. The elastoresistance of the second compound is sign-reversing and can be approximated with the sum of two Curie-Weiss–type terms with opposite signs and different critical temperatures. We attribute this behavior to the competition of contributions to the elastoresistance from different band valleys. These competing contributions may appear since the composition of our compound is close to the critical point at which the low-temperature ground state in the 11 series of iron-based superconductors changes from electronic nematic order to magnetic order.