Condensed Matter Physics contains original and review articles in the field of statistical mechanics and thermodynamics of equilibrium and nonequilibrium processes, relativistic mechanics of interacting particle systems.The main attention is paid to physics of solid, liquid and amorphous systems, phase equilibria and phase transitions, thermal, structural, electric, magnetic and optical properties of condensed matter. Condensed Matter Physics is a diamond open-access, international peer-reviewed scientific journal published quarterly. ISSN 1607-324X (print), 2224-9079 (online) Key title: Condensed Matter Physics Abbreviated key title: Condens. Matter Phys.
Yukhnovskii Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
Investigation of density of states and charge carrier mobility in amorphous semiconductors via time-of-flight photocurrent analysis
The present study examines the electronic transport characteristics of amorphous semiconductors through ToF measurements and numerical simulations. The primary objective is to determine the DOS in amorphous selenium (a-Se) and to assess the temperature and electric field dependence of the hole mobility. A comprehensive investigation of localized states within the mobility gap is performed using Laplace transform analysis of ToF photocurrent transients, combined with the multiple trapping model. This approach enables accurate reconstruction of the DOS across a wide temperature range, allowing clear identification of shallow and deep trap levels and revealing thermally activated transport mechanisms. Simulated ToF currents are also used to evaluate the hole drift mobility under various thermal and field conditions. Activation energies are extracted from Arrhenius plots of the mobility data. The results support a physically consistent description of the electronic structure in a-Se and validate the applicability of Laplace-based techniques for probing charge transport in disordered semiconductors.
Copyright (c) 2025 F. Serdouk, A. Boumali, M. L. Benkhedir, Y. Goutal https://creativecommons.org/licenses/by/4.0
First principle study of electronic, magnetic and thermoelectric properties of Co2YPb (Y = Tc, Ti, Zr and Hf) full Heusler: Application to embedded automotive systems
In this study, theoretical investigation on structural, electronic, magnetic, elastic and thermoelectric properties of the full Heusler Co2YPb (Y = Tc, Ti, Zr and Hf) alloys have been performed within density functional theory (DFT). The exchange and correlation potential is addressed using two approximations: the generalized gradient approximation (GGA) and the GGA augmented by the Tran–Blaha-modified Becke–Johnson (mBj-GGA) approximation, which provides a more accurate description of the energy band gap. The electronic and magnetic properties reveal that the full-Heusler alloys Co2YPb (with Y = Tc, Ti, Zr, and Hf) display half-metallic ferromagnetic behavior. Furthermore, the elastic properties suggest that Co2YPb are mechanically stable, with ductile characteristics. p-type full Heusler alloys exhibit positive Seebeck coefficients and high ZT values, indicating good thermoelectric performance in terms of electrical and thermal conductivity. This leads us to the conclusions that these compounds are very interesting in improving the performance of embedded automotive systems and can also be used in spintronic devices.
Copyright (c) 2025 N. Saidi, A. Abbad, W. Benstaali, K. Bahnes https://creativecommons.org/licenses/by/4.0
Be and Be-related impurities in diamond: density functional theory study
First-principles density functional simulations were employed to investigate the geometries, electrical properties, and hyperfine structures of various beryllium-doped diamond configurations, including interstitial (Bei), substitutional (Bes), and beryllium-nitrogen (Be-N) complexes. The incorporation of Be into the diamond lattice is more favorable as a substitutional dopant than as an interstitial dopant, although both processes are endothermic. Interstitial Be could potentially exhibit motional averaging from planar to axial symmetry with an activation energy of 0.1 eV. The most stable Bes configuration has Td symmetry with a spin state of S = 1. Co-doping with nitrogen reduces the formation energy of Bes-Nn (n = 1–4) complexes, which further decreases as the number of nitrogen atoms increases. This is attributed to the smaller covalent radius of nitrogen compared to carbon, resulting in reduced lattice distortion. Bes-N3 and Bes-N4 co-doping introduces shallow donors, while Bes exhibits n-type semiconductivity, but the deep donor level renders it impractical for room-temperature applications. These findings provide valuable insights into the behavior of beryllium as a dopant in diamond and highlight the potential of beryllium-nitrogen co-doping for achieving n-type diamond semiconductors.
Copyright (c) 2025 K. M. Etmimi, M. A. Ojalah, A. M. Abotruma https://creativecommons.org/licenses/by/4.0
A computational study of thermoelectric conversion in the PbSexTe1−x semiconductor alloys
The present theoretical study focuses on the structural, electronic and thermoelectric properties of PbTe, PbSe and their ternary alloys PbSexTe1−x, using the density functional theory (DFT) by the full potential linearised augmented plane wave (FP-LAPW) method implemented in Wien2k code. Structural properties were performed by using the generalized gradient approximation of Perdew Burke and Ernzenhof (GGA-PBE) scheme. The results show that the calculated lattice parameters are in good agreement with theoretical data previously obtained. For electronic properties, we noticed that for all the compounds of PbSexTe1−x, we have a direct band gap in L point. For thermoelectric properties, we used BoltzTraP2 code and Gibbs2 code. Our results show that the PbSexTe1−x compounds have reached a value of 2.55 for the figure of merit, which indicates that our material is a good thermoelectric candidate.
Copyright (c) 2025 M. Kaid Slimane, B. N. Brahmi, M. Bouchenaki, S. Bekhechi https://creativecommons.org/licenses/by/4.0
Shape descriptors of equilibrium states in a quantum lattice model with local multi-well potentials: A geometric analysis near the phase transitions in Sn2P2S6 ferroelectric crystals
We analyze the equilibrium states of quantum lattice model with local multi-well potentials for Sn2P2S6 ferroelectric crystals using the mean and Gaussian curvatures (H, K), curvedness (C) and shape index (S). From the energy gap, pressure and temperature variations of H, K, C and S, we have reported the geometric construction of the free energy surfaces for the ferroelectric and paraelectric phases. Their behaviors are explicitly observed near the ferroelectric-paraelectric phase transitions. It is found that H, C and S display a cusp singularity at the criticality while K converges to zero on both sides of the critical and tricritical points.
Copyright (c) 2025 S. Özüm, T. Akkurt, R. Erdem, N. Güçlü https://creativecommons.org/licenses/by/4.0
Absorption and scattering of light by metal-dielectric nanoeggs
The optical and plasmonic properties of metal-dielectric nanoeggs were investigated in this study. Frequency dependencies of polarizability, absorption and scattering cross-sections, and radiation efficiency were determined. Expressions describing the size-dependent behavior of surface plasmon resonance frequencies were derived. The causes of blue and red shifts in the maxima of polarizability, absorption, and scattering cross-sections as well as variations in their number and amplitude were identified. Recommendations were proposed regarding the use of materials with maximum radiation efficiency in different spectral ranges.
absorption and scattering cross-sections
Copyright (c) 2025 A. Korotun, R. Korolkov, R. Malysh, R. Kulykovskyi https://creativecommons.org/licenses/by/4.0
Three-dimensional unfrustrated and frustrated quantum Heisenberg magnets. Specific heat study
We examine the S = 1/2 Heisenberg magnet on four three-dimensional lattices — simple-cubic, diamond, pyrochlore, and hyperkagome ones — for ferromagnetic and antiferromagnetic signs of the exchange interaction in order to illustrate the effect of lattice geometry on the finite-temperature thermodynamic properties with a focus on the specific heat c(T). To this end, we use quantum Monte Carlo simulations or high-temperature expansion series complemented with the entropy method. We also discuss a recent proposal about hidden energy scale in geometrically frustrated magnets.
Сollection of the articles dedicated to the 100th anniversary of Prof. Ihor Yukhnovskii
Copyright (c) 2025 T. Krokhmalskii, T. Hutak, O. Derzhko https://creativecommons.org/licenses/by/4.0
Ab initio study of mechanical and functional properties of novel CaZnC and CaZnSi half-Heusler materials
This research work introduces the DFT through FP-LAPW+lo technique in WIEN2k software to obtain information about structural, thermoelectric, and optoelectronic characteristics of CaZnC and CaZnSi materials. The structural optimization was performed using PBE-GGA functional, while the rest of the characteristics were obtained with the PBE-GGA + TB-mBJ approach. The thermoelectric parameters were evaluated using BoltzTraP software. The elastic constants and other mechanical parameters were computed by utilizing the ELAST code within the WIEN2k software, while the thermodynamic characteristics were evaluated using the Gibbs2 program. The findings show a correlation between atomic composition and lattice dimensions while finding that CaZnC has a direct (Γ–Γ) band gap of 1.186 eV, whereas CaZnSi has an indirect (Γ–X) band gap of 1.067 eV. The optical studies of the compounds show potential applications for photovoltaics while the thermoelectric results find optimized power factors and figure of merit values for energy conversion performance. The elastic parameters of CaZnC and CaZnSi demonstrate material stability and brittleness. Lastly, the thermodynamic evaluations provide information about the thermal mechanism and disorder of the materials. As a result, this research work provides significant advancements in the understanding of the fundamentals of these compounds and highlights their promising applications in renewable energy technologies.
Copyright (c) 2025 P. K. Kamlesh, U. K. Gupta, S. Verma, M. Rani, Y. Toual, A. S. Verma https://creativecommons.org/licenses/by/4.0
Link of the Zitterbewegung with the spin conductivity and the spin-textures of multiband systems
The Zitterbewegung phenomenon in multiband electronic systems is known to be subtly related to the charge conductivity, Berry curvature and the Chern number. Here we show that some spin-dependent properties as the optical spin conductivity and intrinsic spin Hall conductivity are also entangled with the Zitterbewegung amplitudes. We also show that in multiband Dirac-type Hamiltonians, a direct link between the Zitterbewegung and the spin textures and spin transition amplitudes can be established. The later allow us to discern the presence or not of the Zitterbewegung oscillations by simply analyzing the spin or pseudospin textures. We provide examples of the applicability of our approach for Hamiltonian models that show the suppression of specific Zitterbewegung oscillations.
Copyright (c) 2025 F. Mireles, E. Ortiz https://creativecommons.org/licenses/by/4.0
50 years of Yukhnovskii’s critical point theory: its place in the constant flow of theoretical physics
Half a century ago, Ihor Yukhnovskii elaborated a method of studying the critical point of the three-dimensional Ising model based on a layer-by-layer integration in the space of collective variables. His method was an alternative to that based on the ε-expansion for which K. G. Wilson was awarded the Nobel Prize in Physics in 1982. However, Yukhnovskii’s technique, which yielded similar results, provided even deeper insight into the nature of this phenomenon. At that time, we, professor’s students, saw only this aspect of his theory. Later, I realized that the mentioned Yukhnovskii’s work naturally fits into a more general context of the turbulent development of quantum field theory and statistical physics in the last quarter of the twentieth century. The aim of the present article is to look at the main aspects and the impact of Yukhnovskii’s theory from this perspective.
Copyright (c) 2025 Yu. Kozitsky https://creativecommons.org/licenses/by/4.0
Critical exponents of the Ising model with quenched structural disorder and long-range interactions at spatial dimension d = 3
We analyse the critical properties of a weakly diluted (random) Ising model with the long-range interaction decaying with distance x as ∼ x - d - σ in a d-dimensional space. It is known to belong to a new long-range random universality class for certain values of the decay parameter σ. Exploiting the field-theoretic renormalization group approach within the minimal subtraction scheme, we compute the three-loop renormalization group functions. On their basis, with the help of asymptotic series resummation methods, we estimate the correlation length critical exponent ν characterising the new universality class for d = 3 and for those values of σ for which long-range interactions are relevant for the critical behaviour.
Copyright (c) 2025 D. Shapoval, M. Dudka https://creativecommons.org/licenses/by/4.0
Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
The self-assembly behavior of a diblock copolymer/homopolymer induced by Janus nanorods
We employ cell dynamics simulation based on the CH/BD model to investigate the self-assembly behavior of a mixed system consisting of diblock copolymers (AB), homopolymers (C), and Janus nanorods. The results indicate that, at different component ratios, the mixed system undergoes various phase transitions with an increasing number of nanorods. Specifically, when the homopolymer component is 0.40, the mixed system transitions from a disordered structure to a parallel lamellar structure, subsequently to a tilted layered structure, and ultimately to a perpendicular lamellar structure as the number of nanorods increases. To explore this phenomenon in greater depth, we conduct a comprehensive analysis of domain sizes and pattern evolution. Additionally, we investigate the effects of the repulsive interaction strength between polymers, wetting strength, length of nanorods, and degree of asymmetry on the self-assembly behavior of the mixed system. This research provides significant theoretical and experimental insights for the preparation of novel nanomaterials.
Copyright (c) 2025 Y. Q. Guo, J. Liu, H. R. He, N. Wu, J. J. Zhang https://creativecommons.org/licenses/by/4.0
Algebraic solution and thermodynamic properties of graphene in the presence of minimal length
Graphene is a zero-gap semiconductor, where the electrons propagating inside are described by the ultrarelativistic Dirac equation normally reserved for very high energy massless particles. In this work, we show that graphene under a magnetic field in the presence of a minimal length has a hidden su(1, 1) symmetry. This symmetry allows us to construct the spectrum algebraically. In fact, a generalized uncertainty relation, leading to a non-zero minimum uncertainty on the position, would be closer to physical reality and allow us to control or create bound states in graphene. Using the partition function based on the Epstein zeta function, the thermodynamic properties are well determined. We find that the Dulong–Petit law is verified and the heat capacity is independent of the deformation parameter.
Copyright (c) 2025 J. Gbètoho, F. A. Dossa, G. Y. H. Avossevou https://creativecommons.org/licenses/by/4.0
Generalised two-dimensional nonlinear oscillator with a position-dependent effective mass and the thermodynamic properties
We investigate a two-dimensional nonlinear oscillator with a position-dependent effective mass in the framework of nonrelativistic quantum mechanics. Using the Nikiforov-Uvarov method, we obtain exact analytical expressions for the energy spectrum and wave functions. Based on the canonical partition function, we derive key thermodynamic quantities, including internal energy, specific heat, free energy, and entropy. Our results show that, unlike the one-dimensional case, where the specific heat is unaffected by the nonlinearity parameter k, the two-dimensional system exhibits a strong k−dependence. At high temperatures, the specific heat becomes temperature-independent for fixed values of k, in line with the Dulong–Petit law. However, these behaviors occur only for negative values of k. These findings highlight the impact of effective mass nonlinearity on macroscopic thermodynamic quantities and suggest that tuning the parameter k could serve as an effective strategy for enhancing the performance of quantum devices, including thermal machines and optoelectronic components.
Copyright (c) 2025 S. E. Bokpe, F. A. Dossa, G. Y. H. Avossevou https://creativecommons.org/licenses/by/4.0
The influence of dimensional crossover on phase transitions and critical phenomena in condensed systems
This article is aimed at studying the effects of the dimensional crossover (DC) on physical properties of condensed systems near phase transition and critical points. Here we consider the following problems: (1) the theoretical provisions that allow to study the effect of spatial confinement on DC near phase transition and critical points; (2) the study of DC in condensed systems with the Ginzburg number Gi < 1, where fluctuation effects are described in different ways at the fluctuation, regular and intermediate (crossover) regions; (3) two types of DC were investigated: (a) a decrease in the linear dimensions L to the values of the correlation length of the order parameter fluctuations leads to the conversion of the dependence on thermodynamic variable into a dependence on linear sizes of 3D systems, as well as (b) a further decrease in linear sizes L the 3D–2D or 3D1D DC happens depending on slitlike or cylindrical geometry, which is determined by the value of the lower crossover dimensionality dLCD; (4) it is proposed to extend the known equalities for critical exponents by using the Mandelbrot formula for fractal dimension Df as a critical exponent; (5) the influence of 3D–2D DC on the characteristics of the fine structure of the molecular light scattering (MLS) spectrum is studied.
Copyright (c) 2025 O. V. Chalyi, E. V. Zaitseva https://creativecommons.org/licenses/by/4.0
Thermodynamic relation for the systems with inhomogeneous distribution of particles
For the system with inhomogeneous distribution of macroscopic parameters we obtain thermodynamic relation which depends on the spatial point(coordinate). In our approach, to obtain such a relation we use the basic ideas of the method of nonequilibrium statistical operator combined with the Hubbard–Stratonovich transformation. First of all, we define the thermodynamic relation for the system with homogeneous distribution of particles. Possible behavior peculiarities of systems with different character of interaction in nonequilibrium case are predicted. By saddle-point method we find the dominant contributions to the partition function and obtain all thermodynamic parameters of the systems with different character of interaction. The formations of saddle state in all systems of interacting particles at different temperatures and particle distributions have the same physical nature and therefore they can be described in the same way. We consider the systems with attractive and repulsive interactions as well as self-gravitating systems.
Copyright (c) 2025 A. P. Rebesh, B. I. Lev, A.G. Zagorodny https://creativecommons.org/licenses/by/4.0
Phase stability and structural properties of the KxCa1-xN novel ferromagnetic alloy from ﬁrst-principles
We study the structural properties and phase stability of the KxCa1−xN alloy using the regular-solution model based on the total energy of the mixing. The pseudopotential approach was used along with PBE functional of Perdew, Burke, and Ernzerhof (PBE). We investigated the bond-lengths distribution as a function of composition x. We also predicted the phase separation of the two partially miscible components and calculated the enthalpy ∆H using the interaction parameter Ω. We observe an asymmetry about x = 0.46 in the phase diagram due to the x-dependant interaction parameter Ω = 12.69 − 1.32x kcal/mole. The equilibrium solubility limit, known as the miscibility gap is found to be around 3033 K.
Copyright (c) 2025 K. Larbaoui, A. Lakdja, G. Bassou https://creativecommons.org/licenses/by/4.0
Beyond conventional half-metals: gapless states and spin gapless semiconducting behavior in X2MnGa (X =Ti, Ir) Heusler compounds
The search for high-performance spintronic materials motivates the exploration of Heusler alloys with unconventional electronic properties. Using density functional theory with Hubbard correction (DFT+U, U = 4 eV), we investigate X2MnGa (X = Ti, Ir) alloys, which stabilize in the ferromagnetic L21-type structure with strong thermodynamic stability. Electronic structure calculations reveal contrasting behaviors: Ti2MnGa transitions from a metallic L21-type phase to a spin gapless semiconductor (SGS) in the XA-type, while Ir2MnGa exhibits gapless half-metallicity behavior in the L21-type but becomes half-metallic in the XA-type. The magnetic properties are governed by spd hybridization between Mn-3d and X-d/Ga-p states, which stabilizes ferromagnetism and tailors electronic states near the Fermi level. The Hubbard U correction proves essential for accurately describing the correlated Mn-3d electrons. These alloys combine structural stability with tunable electronic and magnetic properties, offering a promising platform for spin-polarized transport in next-generation spintronic devices.
Copyright (c) 2025 N. Bouteldja, N. Hacini, I. Ouadha, H. Rached https://creativecommons.org/licenses/by/4.0
Tripartite entanglement in mixed-spin triangle trimmer
Heisenberg model spin systems offer favourable and manageable physical settings for generating and manipulating entangled quantum states. In this work mixed spin-(1/2,1/2,1) Heisenberg spin trimmer with two different but isotropic Landé g-factors and two different exchange constants is considered. The study undertakes the task of finding the optimal parameters to create entangled states and control them by external magnetic field. The primary objective of this work is to examine the tripartite entanglement of a system and the dependence of the tripartite entanglement on various system parameters. Particularly, the effects of non-conserving magnetization are in the focus of our research. The source of non-commutativity between the magnetic moment operator and the Hamiltonian is non-uniformity of g-factors. To quantify the tripartite entanglement, an entanglement measure refered to as “tripartite negativity” has been used in this work.
Copyright (c) 2025 Zh. Adamyan, V. Ohanyan https://creativecommons.org/licenses/by/4.0
Liquid-gas state regularities as a manifestation of global isomorphism with the Ising model
Liquid-gas equilibrium is considered using the global isomorphism with the Ising-like (lattice gas) model. Such an approach assumes the existence of the order parameter in terms of which the symmetry of binodal is restored not only in the vicinity of the critical point (critical isomorphism) but also globally in the whole coexistence region. We show how the empirical law of the rectilinear density diameter of the liquid-gas binodal allows us to derive a rather simple form of the isomorphism transformation between the fluid and lattice gas model of Ising-type. The relations for critical parameters which follow from such isomorphism are tested on a variety of fluid systems, both real and model ones. Moreover, we consider the phase equilibrium in polymer solutions and the Flory θ-point as the extreme state of such equilibrium within our approach. The most crucial testing in 2D case is using the Onsager exact solution of the Ising model, and we represent the results of our approach to the calculation of critical point parameters of monolayers for noble gases and the surface tension.
Copyright (c) 2025 L. A. Bulavin, V. L. Kulinskyi, A. M. Katts, A. M. Maslechko https://creativecommons.org/licenses/by/4.0
Statistical theory of charged particle systems including triple bound states — and the Collaboration Lviv–Rostock
Honoring the hundredth anniversary of the birthday of Ihor R. Yuknovskii we analyze new developments in the statistical thermodynamics of Coulomb systems. The basic idea of this work is to demonstrate that the exponential potential used in the first papers of Yukhnovskii is an appropriate reference system for a description of classical and quantum charged particle systems. We briefly discuss the collaboration between the groups of Ihor R. Yuknovskii in Lviv and Günter Kelbg in Rostock and analyze several approaches based on pair correlation functions and cluster expansion in the classical as well as in the quantum case. Finally, we discuss the progress in the statistical description of bound states of three particles as in helium plasmas and in MgCl2-solutions in the classical case and present new results regarding the influence of three-particle bound states. In particular, we give new expressions for the cluster integrals and the mass action functions of helium atoms and ionic triple associates as well as for the equation of state (EoS).
Copyright (c) 2025 W. Ebeling https://creativecommons.org/licenses/by/4.0
Mutual effect of charge- and number-density correlations in ionic liquids and concentrated electrolytes
Correlation functions in concentrated ionic systems are studied within the mesoscopic theory at the level of the Gaussian approximation. The previously neglected fluctuation contribution to the inverse charge-charge correlation function is taken into account to verify the accuracy of the previous results. We calculate the correlation lengths and the amplitudes and show that the fluctuation contribution does not lead to significant changes of the results. We also derive necessary conditions for the presence of both, the oscillatory and the monotonic decays of the charge-charge correlations that must be satisfied by the noncoulombic contributions to the inverse charge-charge correlation function. At the level of the Gaussian approximation, these conditions are not satisfied. Extension of the theory beyond the Gaussian approximation is necessary to verify whether the asymptotic decay of the charge-charge correlations is monotonous or oscillatory, as suggested by the surface force apparatus or by the SAXS experiments, respectively.
Copyright (c) 2025 O. Patsahan, A. Ciach https://creativecommons.org/licenses/by/4.0
Replica RISM molecular solvation theory for electric double layer in nanoporous materials
Applications of 3D-RISM-KH molecular solvation theory range from solvation energy of small molecules to phase behavior of polymers and biomolecules. It predicts the molecular mechanisms of chemical and biomolecular systems. Replica RISM-KH-VM molecular solvation theory predicts and explains the structure, thermodynamics, and electrochemistry of electrolyte solutions sorbed in a nanoporous material. It was tested on nanoporous carbon supercapacitors with aqueous electrolyte and nanoporous electrosorption cells. The mechanisms in these systems are steered by the electric double layer potential drop across the Stern layer at the nanopores surface and the Gouy-Chapman layer averaged over the nanoporous material, the osmotic term due to the ionic concentrations difference in the two nanoporous electrodes and in the electrolyte solution outside, and the solvation chemical potentials of sorbed ions averaged over the nanoporous material. The latter strongly depends on chemical specificity of ions, solvent, surface functional groups, and steric effects for solvated ions confined in nanopores.
Copyright (c) 2025 A. Kovalenko https://creativecommons.org/licenses/by/4.0
Method of canonical transformations in the theory of quantum gases interacting with radiation
An approach to the theoretical study of effects and phenomena in quantum gases interacting with radiation is proposed. The approach is based on a modification of the canonical transformation method, which was once used to diagonalize Hamiltonians describing the interaction of electrons with phonons in a solid. The capabilities of the method are demonstrated by studying the influence of photons on the spectral characteristics of atoms of quantum gases interacting with radiation. Within the framework of the developed approach, the effect of “dressing” atoms of quantum gases by a cloud of virtual photons is investigated and expressions for the energy characteristics of such dressed atoms — quasiparticles are obtained. The problem of defining the concept of the effective mass of such quasiparticles is discussed.
Copyright (c) 2025 M. S. Bulakhov, A. S. Peletminskii, P. P. Kostrobij, I. A. Ryzha, Yu. V. Slyusarenko https://creativecommons.org/licenses/by/4.0
Effective and asymptotic scaling in a one-dimensional billiard problem
The emergence of power laws that govern the large-time dynamics of a one-dimensional billiard of N point particles is analysed. In the initial state, the resting particles are placed in the positive half-line x ≥ 0 at equal distances. Their masses alternate between two distinct values. The dynamics is initialized by giving the leftmost particle a positive velocity. Due to elastic inter-particle collisions, the whole system gradually comes into motion, filling both right-hand and left-hand half-lines. As shown by [Chakraborti S., Dhar A., Krapivsky P., SciPost Phys., 2022, 13, 074], an inherent feature of such a billiard is the emergence of two different modes: the shock wave that propagates in x ≥ 0 and the splash region in x < 0. Moreover, the behaviour of the relevant observables is characterized by universal asymptotic power-law dependencies. In view of the finite size of the system and of finite observation times, these dependencies only start to acquire a universal character. To analyse them, we set up molecular dynamics simulations using the concept of effective scaling exponents, familiar in the theory of continuous phase transitions. We present results for the effective exponents that govern the large-time behaviour of the shock-wave front, the number of collisions, the energies and momentum of different modes and analyse their tendency to approach corresponding universal values.
Copyright (c) 2025 T. Holovatch, Yu. Kozitsky, K. Pilorz, Yu. Holovatch https://creativecommons.org/licenses/by/4.0
Excluded volume effect of surfactant ligands on the shape of nascent nanocrystal
We investigate the effect of the excluded volume of surfactant ligands on the shape of incipient quantum dots (QDs) to which they are attached. We consider a model in which ligands are represented by hard-sphere particles that are bound to the surface of a nanoparticle (NC) that is cast in the shape of a prism. It is found in Monte Carlo simulations that the ensemble of relevant NC conformations consists of a small number of specific states that take on the form of nanoplates and nanorods. The shape of these states can be well described by the derived theoretical models. At increasing ligand density, the free energy of different states is seen to be approximately the same, suggesting that excluded volume interactions among ligands acts to narrow down the conformational space accessible to an NC without creating a statistical preference for any particular configuration.
Copyright (c) 2025 A. Baumketner, D. Anokhin, Ya. Patsahan https://creativecommons.org/licenses/by/4.0
Elastic properties of fluid mercury across the metal-nonmetal transition: Ab initio simulation study
We report an ab initio molecular dynamics study of fluid mercury at temperature 1750 K in the range of densities 7–13.5 g/cm3 . Along this isothermal line we performed an analysis of total charge fluctuations, which make evidence of neutral atom-like screening in fluid Hg for densities less than 9.25 g/cm3 , which practically coincides with the emergence of the gap in electronic density of states. High-frequency shear modulus, high-frequency and adiabatic speeds of sound, shear viscosity, Maxwell relaxation time and dispersion of collective excitations are analyzed as a function of density along the isothermal line.
Copyright (c) 2025 T. Bryk, O. Bakai, A. P. Seitsonen https://creativecommons.org/licenses/by/4.0
A consistent description of the kinetic processes of electrolyte ion transport in a dynamic porous medium
The consistent description of kinetic and hydrodynamic processes is applied to the study of ion transport processes in the ionic solution-porous medium system. A system of equations is obtained for the nonequilibrium single-ion distribution function, the nonequilibrium average value of the energy density of the interaction of solution ions, and the nonequilibrium average value of the number density of particles in a porous medium. Using the fractional calculus technique, a generalized diffusion equation of the Cattaneo type in fractional derivatives is obtained to describe the processes of subdiffusion of particles in a porous medium.
Copyright (c) 2025 P. P. Kostrobij, B. M. Markovych, O. V. Viznovych, M. V. Tokarchuk https://creativecommons.org/licenses/by/4.0
Towards construction of microscopic model for smart coating of a solid surface
The density functional approach for classical associating fluids is used to explore the wetting phase diagrams for model systems consisting of water and graphite-like solid surfaces chemically modified by a small amount of grafted chain molecules. The water-like fluid model is adopted from the work of Clark et al. [Mol. Phys., 104, 3561 (2006)]. It very well describes the bulk water vapor-liquid coexistence. Each chain molecule consists of tangentially bonded hard sphere segments. We focus on the investigation of the growth of water film on such complex substrates and exploration of the wetting behavior. For grafted monomers, the prewetting phase diagrams are similar to the diagrams for water on a non-modified solid surface. However, for grafted trimers and pentamers, a physically much richer behavior is observed and analyzed. Trends of the behavior of the wetting temperature and the prewetting critical temperature on the grafting density and water-segments attraction are discussed in detail.
Copyright (c) 2025 O. Pizio https://creativecommons.org/licenses/by/4.0