2304-9782, 2618-8686, 2405-7223 19 3 2026 1-194

RAR RUS 9-17 0000-0002-2793-5717 Peter the Great St. Petersburg Polytechnic University Filimonov Alexey filimonov@rphf.spbstu.ru

St. Petersburg, Russian Federation

Peter the Great St. Petersburg Polytechnic University Bondarenko Vyacheslav vyacheslav.b.bondarenko@mail.ru Effect of semiconductor self-compensation on the inhomogeneities of the effective schottky barrier in III-nitride-based contacts This paper examines Schottky barrier contact structures based on III-nitrides. Using the concept of discrete charge distribution of electroactive defects in the semiconductor depletion region, inhomogeneities in the Schottky barrier height have been analyzed, taking into account the mirror image forces. Characteristic quantities and scales of effective barrier changes in the contact were determined, caused by fluctuations in the electric fields of charged impurity atoms and threading misfit dislocations. The average inhomogeneities in the effective Schottky barrier height were shown to reach values of approximately 100 meV while strong semiconductor compensation due to carrier trapping at dislocation states (i.e., the self-compensation effect) took place. The possibility of minimizing these inhomogeneities by selecting the semiconductor doping level was demonstrated. 10.18721/JPM.19301 538.915 effective Schottky barrier self-compensation of III-nitrides natural size effect Schottky barrier inhomogeneities https://physmath.spbstu.ru/article/2026.89.1/ 01_9-17_19(3)2026.pdf

RAR RUS 18-26 Blagoveschensk State Pedagogical University Baryshnikov Sergey svbar2003@list.ru Blagoveshchensk State Pedagogical University Milinskiy Alexey a.milinskiy@mail.ru Amur State University Stukova Elena lenast@bk.ru Preparation and properties of nanoporous ferroelectric ceramics (Pb0.9Ba0.1)(Zr0.9Ti0.1)O3 The results of the study of the properties of porous ferroelectric ceramics based on lead zirconate with the addition of 10 mol.% barium titanate with an average particle size of 50 nm have been presented in comparison with dense ceramics of the same composition. To obtain the porous ceramics, multiwalled carbon nanotubes were added to the batch in an amount of 2 wt.%. During the sintering process the tubes burned forming pores. Using a number of physical methods, it was found that the synthesis of ceramics based on lead zirconate with the addition of barium titanate nanoparticles leads to the formation of a rhombohedral polar phase. The small particle size of barium titanate accelerates diffusion processes and promotes the formation of thermodynamically equilibrium single-phase solid solutions. The porous ceramics exhibit highly effective spontaneous polarization. 10.18721/JPM.19302 537.226 lead zirconate barium titanate spontaneous polarization permittivity phase transition ferroelectric phase https://physmath.spbstu.ru/article/2026.89.2/ 02_18-26_19(3)2026.pdf

RAR RUS 27-34 0000-0002-4810-2378 N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of RAS Khviyuzov Sergey khviyuzov.s@yandex.ru Northern (Arctic) Federal University named after M. V. Lomonosov Volkov Alexandr a.s.volkov@narfu.ru An analysis of temperature-frequency dependences of specific conductivity of vanilliс acid The values of specific electrical conductivity (SEC) of vanillic acid samples have been measured in the frequency range from 10 mHz to 10 MHz, over a temperature range between 153 and 433 K, using impedance spectroscopy. The frequency dependence of the object’s SEC was shown to obey a power law. Based on the Jonscher equation, three frequency components of the SEC were identified. They were correlated with functional groups involved in charge transfer in the molecule. The conductivity in the low-frequency region was associated with carboxyl and methoxyl groups, and it was with phenolic hydroxyl groups involved in charge transfer in the medium frequency region. The π electrons of the benzene ring of the molecule were charge carriers in the high-frequency region. Based on the Arrhenius equation, the values of the activation energy of conductivity were found. As a result, the hopping mechanism of electrical conductivity in the selected temperature range was proven. 10.18721/JPM.19303 537.9 vanillic acid specific conductivity Jonscher equation Arrhenius equation hopping conductivity https://physmath.spbstu.ru/article/2026.89.3/ 03_27-34_19(3)2026.pdf

RAR RUS 35-51 Peter the Great St. Petersburg Polytechnic University Bashkatov Sergei bashkatov.so@edu.spbstu.ru 0000-0002-4572-4120 Peter the Great St. Petersburg Polytechnic University Sergeev Vladimir v.sergeev@spbstu.ru 0000-0002-1091-6405 Peter the Great St. Petersburg Polytechnic University Kapralov Vladimir vladkap@spbstu.ru Simulation of operational scenarios for a system mitigating the consequences of a discharge disruption in the TRT tokamak This paper presents the results of numerical simulation of the temporal evolution of the plasma current and runaway electron (RE) current suppression in the tokamak reactor facility during a tokamak disruption using the injection of tungsten collectors absorbing REs. The efficiency of methods of the RE current suppression was compared using the collector injection and massive injection of working gas − deuterium. A zero-dimensional approach was used to solve a system of two differential equations for the plasma and RE currents, taking into account RE losses on the tungsten collector that occurred during their passage through the plasma at the discharge current quench stage. The simulation results showed that the most promising disruption mitigation system is a combined one, which initiates the injection of argon or deuterium in the intended disruption scenario and injects argon and three massive (230 g) collectors at velocities of 450 m/s in the unintended disruption scenario. 10.18721/JPM.19304 533.9 tokamak current disruption avalanche current of runaway electrons collector of runaway electrons https://physmath.spbstu.ru/article/2026.89.4/ 04_35-51_19(3)2026.pdf

RAR RUS 52-62 Lipetsk State Pedagogical University named after P. P. Semenov-Tyan-Shansky Filippov Vladimir wwfilippow@mail.ru 0000-0002-9685-9711 Institute of Mathematics and Mechanics of Ural Branch of the RAS; Ural Federal University named after first president of Russia B. N. Yeltsin Ershov Aleksandr An analysis of the accuracy of analytical methods for calculating the DC electric fields in a limited area The presented study aimed to perform a qualitative analysis of two calculated solutions to Neumann boundary value problems for a bounded region using the partition method. The proposed author's solutions have simulated the distribution of electric potential in a rectangular conducting plate through which a direct current passes. A modification of the standard boundary conditions was considered; it involved taking into account the nonuniform current density on the contact surface. A comparison of the results of the application of theoretical computer models obtained on the basis of solutions to the Neumann problems and experimental measurements was carried out. A significant increase in the solution accuracy was shown to achieve near current contacts when using the modified boundary conditions relative to the standard ones. Moreover, the discrepancy between the results obtained by these two calculation methods in the middle region of the sample, turned out to be minimal. 10.18721/JPM.19305 51-73, 537.311.5 Laplace equation Neumann problem electric potential quasi-stationary electric current https://physmath.spbstu.ru/article/2026.89.5/ 05_52-62_19(3)2026.pdf

RAR RUS 63-72 0000-0001-5814-032X Peter the Great St. Petersburg Polytechnic University Gerchikov Leonid 0000-0003-2650-3741 State Marine Technical University Sheinerman Sergei Calculations of photoelectron emission spectra resulting from atomic 1s shell photoionization followed by sequential radiative and Auger decays of inner vacancies Photoelectron emission from 1s-shell photoionization of an argon atom and a carbonyl sulfide (OCS) molecule followed by sequential X-ray radiative and Auger decays has been theoretically studied within ab initio quantum many-body approach. Energy spectra of electron emission are calculated for photoelectrons registered in non-coincident with Auger electrons measurements and compared with experimental data. Prominent post collision interaction distortion of the photoelectron energy spectra is reported. The quantum many-body approach employed provides more accurate description of photoelectron emission than simple approximate model used earlier. 10.18721/JPM.19306 544.171.42 inner-shell photoionization postcollision interaction Auger decay argon atom carbonyl sulfide molecule https://physmath.spbstu.ru/article/2026.89.6/ 06_63-72_19(3)2026.pdf

UNK RUS 73-81 Peter the Great St. Petersburg Polytechnic University Goldberg Ekaterina goldberg_ev@spbstu.ru Peter the Great St. Petersburg Polytechnic University Apushkinsky Evgeniy apushkinsky@hotmail.com 0000-0001-5986-0820 Kozhevnikov Vadim Krukovskaya Lidia lidia.ks@mail.ru 0009-0005-9096-3744 Peter the Great St. Petersburg Polytechnic University Tikhonova Tatiana tihonova_ta@spbstu.ru A setup for investigating the Doppler effect This article presents the description of a setup for conducting experiments on the Doppler effect for acoustic waves and measuring the speed of sound in air. The description covers the operation principle of the setup and its individual components as well as their main technical characteristics. The test results and their comparison with calculated data have been presented for this unit. A qualitative match between them was established. This developed system is used as an educational laboratory setup and can also serve as an equipment prototype for measuring the airflow velocity. It can also be used both to estimate gas consumption and to autonomously determine or monitor the aerial vehicle speed. A key feature of the system is the ability to operate remotely. 10.18721/JPM.19307 534, 53.072 physics Doppler effect acoustic waves air flow velocity remote access https://physmath.spbstu.ru/article/2026.89.7/ 07_73-81_19(3)2026.pdf

REV RUS 82-115 0009-0004-7198-6329 Peter the Great St. Petersburg Polytechnic University Nguyen Van Tu Ahn anh.spbpu@gmail.com 0000-0002-3321-7797 Peter the Great St. Petersburg Polytechnic University Arkhipov Alexander arkhipov@rphf.spbstu.ru University of Toyama Dao Thi Le Dung dung.dl0609@gmail.com

Japan, Toyama

Vietnam Academy of Science and Technology Nguyen Huy Dan dannh@ims.vast.ac.vn

Hanoi, Vietnam

Vietnam Academy of Science and Technology Nguyen Hai Yen yennh@ims.vast.ac.vn

Hanoi, Vietnam

Vietnam Academy of Science and Technology Luong Van Duong duonglv@ims.vast.ac.vn

Hanoi, Vietnam

Institute of Technology Nguyen Minh Tuan tuannm@ims.vast.ac.vn

Hanoi, Vietnam

Peter the Great St. Petersburg Polytechnic University Arkhipov Nikolai nick12arkh@gmail.com Peter the Great St. Petersburg Polytechnic University Sun Haichao sunhaichao1997@gmail.com 0000-0002-6402-8112 Peter the Great St. Petersburg Polytechnic University Louksha Oleg louksha@rphf.spbstu.ru 0000-0002-2519-2577 Peter the Great St. Petersburg Polytechnic University Gabdullin Pavel gabdullin_pg@spbstu.ru Properties and applications of the half-Heusler alloys in thin-film thermoelectric generators for low and medium temperatures This review focuses on half-Heusler MNiSn alloys (M = Ti, Zr, Hf), which are of particular interest for creation of thin-film thermoelectric generators (TEGs) operating in the low- and medium-temperature ranges (300 – 800 K). The paper examines current energy challenges requiring the development of compact and efficient TEGs, as well as the reasons for the increased attention paid to half-Heusler alloys compared to traditional Bi-, Te-based materials. The crystal structure, phase stability, electronic and phononic properties of the alloys, synthesis methods, and alloying strategies are discussed in detail. The results of recent studies on thin-film MNiSn are analyzed, and their potential for flexible TEG architecture, opening new avenues for highly efficient miniature energy devices, is assessed. 10.18721/JPM.19308 621.362 thin film half-Heusler alloy thin-film thermoelectric generator thermoelectric properties https://physmath.spbstu.ru/article/2026.89.8/ 08_82-115_19(3)2026.pdf

RAR RUS 116-124 0009-0001-1698-9162 Ioffe Institute Balysh Zoya 0009-0009-4336-0712 Ioffe Institute Volodina Daria 0000-0003-1344-9483 Grudinkin Sergey grudink@gvg.ioffe.ru 000-0002-7471-4028 Ioffe Institute Eurov Daniil edan@mail.ru Ioffe Institute Kurdyukov Dmitry kurd@gvg.ioffe.ru

St. Petersburg, Russian Federation

0000-0003-4519-0111 Ioffe Institute Glebova Nadezhda Glebova@mail.ioffe.ru 0000-0003-0434-5252 Ioffe Institute Stovpiaga Ekaterina kattrof@gvg.ioffe.ru Porosity characteristics of ultra-high specific surface area silica particles at formation stages Spherical micro-mesoporous submicron particles of amorphous silica with a specific surface area (SSA) up to 2050 m2/g, comparable with that of nanoporous carbon materials, have been synthesized. Particle structure and chemical composition variations were studied by the adsorption porosimetry, thermogravimetric analysis and IR spectroscopy methods at formation stages. Sequential elimination of various organic porogens forming the particles’ structure by washing and annealing in different ambients leading to pore opening and corresponding SSA growth were demonstrated. The distinctive feature of the developed post-treatment procedure is the stabilization of the fragile silica backbone due to the formation of a distributed network of surface silanol groups that maintain the achieved characteristics of high porosity. 10.18721/JPM.19309 54.057 spherical particles silica micropores mesopores ultra-high specific surface area https://physmath.spbstu.ru/article/2026.89.9/ 09_116-124_19(3)2026.pdf

RAR RUS 125-138 0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru 0000-0003-3298-3702 Peter the Great St. Petersburg Polytechnic University Ivanishchev Dmitry ivanishchev_da@pnpi.nrcki.ru 0000-0002-3395-0454 Peter the Great St. Petersburg Polytechnic University Kotov Dmitry dmitriy.kotov@gmail.com 0009-0001-9974-0169 Peter the Great St. Petersburg Polytechnic University Malaev Mikhail mmalayev@gmail.com 0000-0002-3028-8776 Petersburg Nuclear Physics Institute named by B. P. Konstantinov of NRC «Kurchatov Institute» Ryabov Yuri ryabov_yg@pnpi.nrcki.ru The possibilities of measuring the properties of K*(892)0 and φ(1020) resonances in collisions of xenon nuclei with a fixed tungsten target at an energy of 2.5A GeV in the MPD experiment We report the study results of possibilities of measuring the properties of K*(892)0 and φ(1020) resonances in collisions of Xe nuclei with a fixed tungsten target at an energy of 2.5A GeV using the MPD detector at the NICA collider. The evaluations of the mass resolution, detection efficiency of the MPD detector and the transverse momentum spectra for the studied resonances were made. The evaluations were obtained depending on the transverse momentum for different intervals of centrality of Xe + W collisions in the central rapidity range using model calculations. The resonances were reconstructed in the K*(892)0 → K+ + π– and φ(1020) → K+ + K– decay channels. We used an approach based on σ-parameterization of daughter particle identification information in the MPD detector. 10.18721/JPM.19310 539.126.3, 539.126.6 nuclei collision production hadron resonance NICA collider MPD detector https://physmath.spbstu.ru/article/2026.89.10/ 10_125-138_19(3)2026.pdf

RAR RUS 139-149 Peter the Great St. Petersburg Polytechnic University Larionova Dariya dlar@bk.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru 0000-0002-3395-0454 Peter the Great St. Petersburg Polytechnic University Kotov Dmitry dmitriy.kotov@gmail.com Peter the Great St. Petersburg Polytechnic University Trushkov Dmitriy trushkoov@yandex.ru Determination of the centrality of ion-ion collisions under low multiplicity conditions The centrality of ion-ion collisions is an important parameter that defines the initial geometry of the interaction and significantly influences the interpretation of experimental results. Since centrality cannot be measured by direct experiments, various model-dependent methods are used in practice. In SPD (Spin physics detector) experiment located at NICA collider centrality determination is particularly challenging due to low particle multiplicities in small collision systems at low energies, such as Al+Al collisions at √sNN = 10 GeV. In this work, the applicability of traditional centrality determination methods based on charged-particle multiplicities and spectator nucleon energy deposition is investigated under SPD conditions. In addition, the potential for improving centrality determination by using a set of experimental observables and machine-learning techniques based on decision tree classifiers is explored. 10.18721/JPM.19311 539.125.4, 539.126.3 centrality ion-ion collisions SPD experiment collider low multiplicity machine learning https://physmath.spbstu.ru/article/2026.89.11/ 11_139-149_19(3)2026.pdf

RAR RUS 150-161 Peter the Great St. Petersburg Polytechnic University Larionova Dariya dlar@bk.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru 0000-0002-3395-0454 Peter the Great St. Petersburg Polytechnic University Kotov Dmitry dmitriy.kotov@gmail.com Peter the Great St. Petersburg Polytechnic University Neumin Dmitry neumin.dv@mail.ru An analysis of identified charged hadron production in Xe + W collisions at 2.5A GeV using the blast-wave model A method for analyzing invariant spectra of charged hadrons in the region of high baryon chemical potentials is presented, aimed at future measurements of the MPD experiment. Within the framework of the blast-wave model, previously published invariant spectra of identified charged hadrons (π±, K±, and p), obtained in Xe+W collisions at an energy of 2.5A GeV using the MPDroot package with the UrQMD generator, were analyzed, and the particle ratios π⁺/π⁻ and K⁺/K⁻ were calculated. The applicability of the Blast-wave model to the description of Xe+W collisions at the energy of 2.5A GeV was investigated. Chemical potentials were estimated from the integrated particle ratios. The obtained values indicated a substantial baryon density in the central region of the collision and, consequently, significant baryon stopping. The results are of a methodological nature and can be used to assess the applicability of standard approaches in the analysis of future MPD experimental data. 10.18721/JPM.19312 539.125.4, 539.126.3 MPD NICA STAR QGP Blast-wave phase diagram nucleat matter baryon stopping https://physmath.spbstu.ru/article/2026.89.12/ 12_150-161_19(3)2026.pdf

RAR RUS 162-170 Peter the Great St. Petersburg Polytechnic University Kruashvili Dmitry kruashvili.dv@edu.spbstu.ru 0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru The double longitudinal spin asymmetry of light pseudoscalar mesons produced in collisions of longitudinally polarized protons The magnitude of the double longitudinal spin asymmetry of π-, K-, and η-mesons generated in collisions of longitudinally polarized protons at energies of 510, 200, and 27 GeV has been analyzed (using Monte Carlo simulation). The simulation was carried out using the Pythia8 software package, which had been previously modified for the task at hand: accounting for spiral parton distribution functions and interaction cross-sections of polarized partons with certain spiralities. A comparison of the simulation results with experimental data for energy values of 510 and 200 GeV from literature sources showed a good agreement. This served as the basis for calculating the results of the planned NICA experiment for the considered mesons at an energy of 27 GeV. 10.18721/JPM.19313 539.12 Pythia8 double longitudinal spin asymmetry distribution function parton cross section https://physmath.spbstu.ru/article/2026.89.13/ 13_162-170_19(3)2026.pdf

RAR RUS 171-182 Peter the Great St. Petersburg Polytechnic University Markvart Aleksandr markvart_aa@spbstu.ru 0009-0009-2008-7266 Peter the Great St. Petersburg Polytechnic University Zavalishina Liubov 0000-0001-5988-1429 Peter the Great St. Petersburg Polytechnic University Liokumovich Leonid leonid@spbstu.ru Peter the Great St. Petersburg Polytechnic University Ushakov Nikolai n.ushakoff@spbstu.ru Simulation of a chirped fiber Bragg grating in a few-mode step-index optical fiber under axisymmetric excitation In this paper, a multimode fiber Bragg grating variant inscribed in a few-mode step-index fiber and operating in dual-mode LP01-LP02 regime has been proposed. The commercially available Thorlabs FG025LJA fiber with a 25-μm core diameter and a numerical aperture of 0.1, as a suitable optical fiber was selected (this fiber exhibits only two axisymmetric modes in the O-band). The self-coupling and cross-coupling coefficients of the modes in the grating and the reflectance spectra of homogeneous and chirped gratings were calculated. The effects of saturation, broadening, and resonance interference, as well as the generation of a single reflection peak with a maximum reflectivity of up to 98% were demonstrated. 10.18721/JPM.19314 535.3, 535-15, 535.417 multimode Bragg grating chirped grating few-mode fiber axisymmetric mode https://physmath.spbstu.ru/article/2026.89.14/ 14_171-182_19(3)2026.pdf