This work studies the effect of a transverse electric field on the resistance of bismuth thin films. The existence of an electric field effect in bismuth thin films on mica and polyimide has been experimentally confirmed. The study obtained experimental dependences of resistance on the transverse electric field strength for bismuth films of various thicknesses on mica and polyimide. It also revealed changes associated with a decrease in the thickness of the film and the material of the used substrate. A qualitative interpretation of the observed effect was given based on the analysis of changes in the mobility of free charge carriers in films depending on the direction of the electric field, as well as the thickness of the film and the substrate material.

The work investigates the thermoelectric effect in mixtures of colloidal solutions with ionic electrolytes in the initial state, when the formation of concentration gradients under the influence of an inhomogeneous temperature field can be neglected. Based on experimental measurements in mixtures with different concentrations of colloidal particles and ions, the conditions under which with the coefficient of thermoelectric electromotive force (EMF) is governed by the ionic subsystem and when the main contribution to the value of the thermoelectric EMF is made by colloidal particles are determined.

The effect of dendritic inhomogeneity in Bi 0 . 88 Sb 0 . 12 crystals on the transport properties and thermo electric Q-factor was studied by experiment. It was found that the thermoelectric Q-factor of dendritic Bi 0 . 88 Sb 0 . 12 crystals grown at a molten zone displacement rate of 1 cm/h exceeds the Q-factor of homogeneous crystals of the same composition by up to 20%.

The paper deals with the results of experiments to investigate the thermoelectrokinetic effect in colloidal solutions of tannin. As the theoretical analysis and results of mathematical modeling show, in the classical formulation of the experiment to measure the thermoelectrokinetic EMF, significant upward free-convective flows should be formed, which significantly distort the temperature and velocity field of the electrically conducting medium. In addition, in this case it is impossible to achieve a significant temperature gradient, the value of thermoelectrokinetic EMF depends on its value. As experiments show, in colloidal solutions of tannin at suppression of free-convective flows a noticeable thermoelectrokinetic effect is observed, which exceeds similar values for solutions of ionic electrolytes.

Since the energy spectrum of bismuth charge carriers is highly sensitive to mechanical deformations, studying their influence, leading to an increase or decrease in the overlap of actual extrema, on the transport properties of charge carriers in ultrathin bismuth films makes it possible to investigate the combination of manifestations of the quantum size effect and metallic surface states. In this work, the temperature dependencies of the electrical and galvanomagnetic properties of thin bismuth films (10-1250 nm) are studied under conditions of in-plane tensile and compressive deformation. Deformations are created as a result of the difference in the coefficients of thermal expansion of the film and substrate materials. Silicon with an oxidized surface, mica, and polished cleavage (111) CaF2 F 2 are used in order to create either tensile and compressive deformations. The presence of film deformations is confirmed by XRD. The magnitude of deformation is calculated based on the CTEs of the materials. The absence of mechanical stress relaxation or the formation of additional defects during temperature measurements is confirmed by the absence of hysteresis of properties in the range of 77-300 K. Based on the experimental results, the mobilities and concentration of charge carriers are calculated within the framework of the two-band model. As the film thickness decreases to less than 100 nm, an increase in the charge carrier concentration is observed, which is associated with metallic surface states. It is shown that the magnitude of the effect of deformation on the concentration of charge carriers in films of all thicknesses remains unchanged.

The paper presents the results of experimental measurements of thermoelectromotive force and electrical conductivity of animal blood samples and Ringer's medical solution, which are similar in their properties and chemical composition to human blood. The influence of the contributions of the ionic component and the contribution of blood corpuscles on the value of the thermoelectromotive force coefficient is analyzed. The effect of dilution with distilled water on thermoelectric properties and electrical conductivity of blood has been studied. The influence of the ionic composition of a model medical Ringer's solution on the coefficient of thermoelectromotive force is analyzed. The experimental results show that the coefficient of thermoelectromotive force of the blood samples under study is determined to a greater extent by the colloidal component of the shaped elements than by the contribution of the ionic subsystem. The results obtained indicate that thermoelectric phenomena in biological fluids can affect the activation of biochemical processes in the body of animals. Keywords: thermoEMF, electrical conductivity, colloidal solutions, blood plasma.

Due to the sensitivity of the electronic structure of semi‐metals to small distortions of the crystal lattice, the study of the electrical and galvanomagnetic properties of bismuth films requires taking into account the deformation that occurs in the film‐substrate system due to the difference in the thermal expansion of the film and substrate materials. The magnitude of these deformations plays an important role in analyzing the temperature dependencies of the transport properties of charge carriers. The paper presents an experimental study of the magnitude of deformation of bismuth films on various substrates at 300 and 77 K using X‐ray diffraction. Changes in the lattice constant of crystallites, the trigonal axis of which is perpendicular to the film plane, depending on the substrate material, are obtained. A comparison between the assessment of the deformation of these crystallites in the film plane based on Hooke's law and the difference in the coefficients thermal expansion of the film and substrate materials is made.

Background. The study considers the thermoelectrokinetic effect, which belongs to a specific class of cross transport phenomena occurring under the simultaneous influence of three thermodynamic forces. The influence of natural convection on the steady-state fluid temperature and velocity fields formed in the presence of the thermoelectrokinetic effect is evaluated. The method of suppression of natural convection in the measurement of thermoelectrokinetic EMF is developed and the corresponding study in aqueous solution of tannin is carried out. Materials and methods. Assessment of the influence of natural convection on the temperature and velocity distributions of the liquid is carried out on the basis of experimental measurements of its temperature field using a laboratory thermal imager and calculations of the corresponding fields on the basis of numerical solution of the Navier- Stokes, heat conduction, and continuity equations by the finite element method. Measurement of thermoelectrokinetic EMF in colloidal tannin solution with suppression of free convection is carried out using a modified experimental setup in which the direction of the temperature gradient is reversed. Results. On the basis of numerical modeling and experimental measurements, the temperature and velocity distributions of the liquid in the Ushaped tube are obtained. The results of numerical calculations agree with the results of insitu experiment. It is shown that in the classical formulation of the experiment to measure thermoelectrokinetic EMF when heating the liquid in a U-shaped tube from below, it is not possible to create a significant temperature drop, on which the value of thermoelectrokinetic EMF depends. The thermoelectrokinetic EDS of colloidal tannin solution was measured under conditions of suppressed convection. Under these conditions, the EMF reaches a significant value. Conclusions. Thus, natural convection significantly affects the manifestation of the thermoelectrokinetic effect in liquid electrically conducting media, and its suppression contributes to the formation of higher temperature gradients. Due to this, the value of thermoelectrokinetic EMF increases.

Based on a thermodynamic ratio between the thermopower coefficient and entropy of the electrically conducting medium, we obtained an estimated value of the thermoelectric efficiency parameter ZT for an electronic system of fully ionised plasma. An example of such a system, which is in the most disordered state, is the electron-nuclear plasma of the Sun. The resulting universal value ZT = (25/6) can be considered as an assessment of the limiting capabilities of thermoelectric energy conversion.

The paper is devoted to the study of transverse electric field effect on transport properties of charge carriers in bismuth and bismuth-antimony thin films. Experimental results reveal the existence of electric field effect in thin films of composition up to 12 at.% Sb. The dependencies of resistance on magnitude of electric field are obtained in a wide range of film thicknesses. A qualitative interpretation of the observed effect is given based on the analysis of the mobility of electrons and holes in films depending on the sign of the electric field and the film thickness.

The paper presents the results of a study of the electrical, galvanomagnetic, and thermoelectric properties of Bi and Bi1-xSbx (x = 0.03, 0.05, and 0.12) thin films (10-50 nm) on a mica substrate. All samples are characterized by an increase in conductivity with a de-crease in film thickness, which can be associated with the presence of topologically protected surface states. It has been found that the band structure of the alloys significantly affects the appearance of the metallic type of conductivity in films with a < 18 nm thickness. It was found that the resistivity of Bi0.97Sb0.03 films < 17 nm thick is almost independent of temperature. Despite the increase in the conductivity of the samples, with a decrease in the thickness, the thermoelectric power factor decreases, which casts doubt on the fact that surface states have a positive effect on the thermoelectric figure of merit of thin Bi1-xSbx films. However, the detection of a positive thermoelectric power in Bi0.88Sb0.12 samples may be of interest in the development of the p branch of thermoelectric converters.

Due to the small indirect overlap of the valence and conduction bands, as well as the small direct band gap sensitive to external impact, bismuth is of great interest for stress engineering of band structure. In this work, we study the effect of uniaxial deformation along the trigonal axis of a bismuth crystal on its band structure using the density functional theory modeling. A transition to the semiconductor state occurs upon compressive deformation along the trigonal axis, as well as a transition to the gapless state at the L-point upon tensile deformation. The obtained results provide a deeper understanding of the patterns of change in the band structure of bismuth under uniaxial deformation and will serve as a basis for the analysis of the experimental results of studying the transport properties of thin bismuth films under conditions of in-plane deformation.

The results of a study of the semimetal films deformation produced by dome bending of the substrate are presented. Deformation control was carried out by means of X-ray diffraction analysis. It is shown that the dome bending method can be used to study films under planar deformation in a film-substrate system with different thermal expansion coefficients. The maximum in-plane deformation for bismuth films of 1 mkm thickness order was found. It was shown that the deformation created by the dome bending of the substrate in combination with the use of substrates with different temperature expansion makes it possible to obtain a relative in-plane deformation of bismuth films up to 0.8% at 300 K.

Background. This work investigates thermoelectric phenomena in solutions of mixtures of electrolytes, which also include colloidal solutions. Thermoelectric and thermal diffusion phenomena in solutions of simple binary electrolytes have been studied in detail, and then there are not enough works devoted to the study of these phenomena in solutions of several electrolytes’ mixtures. Therefore, due to the possibility of using liquid electrolytes and their mixtures in thermoelectrochemical cells designed for direct conversion of low-potential thermal energy into electrical energy, these studies are relevant. Materials and methods. Standard methods are used to measure the coefficient of thermoelectric EMF of solutions of mixtures of ionic electrolytes and colloidal solutions. The analysis of the obtained experimental results is carried out within the framework of the thermodynamics of irreversible processes. Results and conclusions. Based on the analysis of the ratio for the thermodiffusion potential difference obtained in the framework of the thermodynamics of irreversible processes, it is shown that the value of the thermoelectric EMF of such solutions in the initial state is determined by the charged particles of the solution, which have the highest values of the product of the transfer number by the transfer heat. Experimental measurements in solutions of mixtures of ionic electrolytes, colloidal solutions confirm this assumption. It also follows from the analysis of experimental results that when the ratio between the components of an electrolyte mixture changes, its thermoelectric force tends to the value that the component of the mixture having the highest concentration has. This effect is due to the increasing value of the transfer numbers of charged particles with an increase in their concentration.

This paper presents the results of studying the magnitude of the strain of semimetal films created by the dome bending of the substrate. The deformation is controlled by X-ray diffraction (XRD) analysis. It is shown that the dome bending method can be used to study films under conditions of the in-plane deformation that occurs in the film-substrate system due to the difference in the coefficients of thermal expansion of the film and substrate material. It is established that the deformation created by the dome bending of the substrate in combination with the use of substrates with a different thermal expansion makes it possible to obtain a relative in-plane deformation of bismuth films up to 0.8% at 300 K.

The thermoelectric effect is investigated in mixtures of colloidal solutions with ionic electrolytes in the initial state, when the formation of concentration gradients under the influence of an inhomogeneous temperature field can be neglected. Based on experimental measurements in mixtures with different concentrations of colloidal particles and ions, the conditions under with the coefficient of thermoelectric EMF is determined by the ion subsystem and under which the main contribution to the value of the thermoelectric force is made by colloidal particles are determined.

The reasons for increasing the charge carriers concentration in thin bismuth films are discussed. The concentration was calculated on the basis of the measured electrical and galvanomagnetic coefficients at the temperature 77K under the two-band approximation and the assumption that the charge carriers free path in the film is isotropic.

The paper presents the results of experimental measurements of thermoelectromotive force and electrical conductivity of animal blood samples and Ringer's medical solution, which are similar in their properties and chemical composition to human blood. The influence of the contributions of the ionic component and the contribution of blood corpuscles on the value of the thermoelectromotive force coefficient is analyzed. The effect of dilution with distilled water on thermoelectric properties and electrical conductivity of blood has been studied. The influence of the ionic composition of a model medical Ringer's solution on the coefficient of thermoelectromotive force is analyzed. The experimental results show that the coefficient of thermoelectromotive force of the blood samples under study is determined to a greater extent by the colloidal component of the shaped elements than by the contribution of the ionic subsystem. The results obtained indicate that thermoelectric phenomena in biological fluids can affect the activation of biochemical processes in the body of animals.

The study shows that electromagnetic phenomena in the convective plasma zone of the Sun and stars and the local magnetic field near the Sun’s surface are caused not only by the magnetohydrodynamic dynamo mechanism (Krause, Rädler 1980; Moffatt 1978; Morozov 2006), but also by the phenomena that have relatively recently become the focus of research, i. e., thermoelectrokinetic phenomena in the viscous electrically conductive medium in the presence of a temperature gradient (Grabov 2003; 2005a; 2005b; Prigogine, Nicolis 1977). The results of physical modelling and quantitative estimates show that thermoelectrokinetic currents can create primary magnetic fields of approximately B ≅ 103 Gs in the convective plasma zone of the Sun and stars.