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Metal halide perovskites have brought about a disruptive shift in the field of third-generation photovoltaics. Their potential as remarkably efficient solar cell absorbers was first demonstrated in the beginning of the 2010s. However, right from their inception, persistent challenges have impeded the smooth adoption of this technology in the industry. These challenges encompass issues such as the lack of reproducibility in fabrication, limited mid- and long-term stability, and concerns over toxicity. Despite achieving record efficiencies that have outperformed even well-established technologies, such as polycrystalline silicon, these hurdles have hindered the seamless transition of this technology into industrial applications. In this Perspective, we discuss which of these challenges are rooted in the unique dual nature of metal halide perovskites, which simultaneously function as electronic and ionic semiconductors. This duality results in the intermingling of processes occurring at vastly different timescales, still complicating both their comprehensive investigation and the development of robust and dependable devices. Our discussion here undertakes a critical analysis of the field, addressing the current status of knowledge for devices based on halide perovskites in view of electronic and ionic conduction, the underlying models, and the challenges encountered when these devices are optoelectronically characterized. We place a distinct emphasis on the positive contributions that this area of research has not only made to the advancement of photovoltaics but also to the broader progress of solid-state physics and photoelectrochemistry. [ABSTRACT FROM AUTHOR]

Pressure-induced phase transformation in iron and its alloys is a classic research topic in solid-state physics, material science, and geophysics. The crystal structure of iron undergoes a phase transformation at a hydrostatic pressure of 13 GPa, changing from a body-centered cubic system to a hexagonal close-packed system. Although extensive research has been carried out on the transformation in iron by using molecular dynamics simulations, there is very limited literature that focuses on the contribution of parent phase orientations, system size, and impurities to the phase evolution. In this work, classic molecular dynamics simulations have been employed to investigate the effects of system size, lattice orientation, and impurity concentration on the pressure-induced phase transformation of iron and iron alloys for the first time. Our results show that the lattice orientation has a strong influence on the phase transition behavior, while the influence of carbon is small. The phase transition is slightly delayed with increasing carbon content, whereas the transition pressure increases from [001] to [011] to [111] orientation. The amount of twinning and stacking faults highly depends on the orientation. It is easiest for solitary waves to travel through [111] lattice orientation. The addition of carbon has a slow-down effect on shock velocities, and this effect increases with carbon content and lattice orientation of the samples from [001] to [011] to [111]. [ABSTRACT FROM AUTHOR]

The adiabatic connection interaction strength interpolation (ISI)-like method provides a high-level expression for the correlation energy, being, in principle, exact not only in the weak-interaction limit, where it recovers the second-order Görling–Levy perturbation term, but also in the strong-interaction limit that is described by the strictly correlated electron approach. In this work, we construct a genISI functional made accurate for the uniform electron gas, a solid-state physics paradigm that is a very difficult test for ISI-like correlation functionals. We assess the genISI functional for various jellium spheres with the number of electrons Z ≤ 912 and for the non-relativistic noble atoms with Z ≤ 290. For the jellium clusters, the genISI is remarkably accurate, while for the noble atoms, it shows a good performance, similar to other ISI-like methods. Then, the genISI functional can open the path using the ISI-like method in solid-state calculations. [ABSTRACT FROM AUTHOR]

In solid state physics, electronic properties of crystalline materials are often inferred from the spectrum of periodic Schrödinger operators. As a consequence of Bloch's theorem, the numerical computation of electronic quantities of interest involves computing derivatives or integrals over the Brillouin zone of so-called energy bands, which are piecewise smooth, Lipschitz continuous periodic functions obtained by solving a parametrized elliptic eigenvalue problem on a Hilbert space of periodic functions. Classical discretization strategies for resolving these eigenvalue problems produce approximate energy bands that are either non-periodic or discontinuous, both of which cause difficulty when computing numerical derivatives or employing numerical quadrature. In this article, we study an alternative discretization strategy based on an ad hoc operator modification approach. While specific instances of this approach have been proposed in the physics literature, we introduce here a systematic formulation of this operator modification approach. We derive a priori error estimates for the resulting energy bands and we show that these bands are periodic and can be made arbitrarily smooth (away from band crossings) by adjusting suitable parameters in the operator modification approach. Numerical experiments involving a toy model in 1D, graphene in 2D, and silicon in 3D validate our theoretical results and showcase the efficiency of the operator modification approach. [ABSTRACT FROM AUTHOR]

Textbooks often present the phenomenon of screening within the Thomas–Fermi model for three-dimensional free electron gases, but obtaining the dielectric response function and screening potential for dielectric systems of reduced dimensionality is also of pedagogical interest. In this work, we introduce a simple approach to investigate static screening in dielectric systems in the presence of an impurity charge for different dimensionalities. This approach is applicable to semiconductors and insulators alike. We demonstrate that, in 3D systems, the macroscopic dielectric function in reciprocal space is a constant, while in 2D and 1D systems, it strongly depends on the momentum transferred to the electrons in the dielectric. Through the proposed dielectric screening model, one can also determine binding energies in a hydrogenic model that can be used to describe excitations in real semiconductor systems. Screening in dielectrics is a measure of the strength of Coulomb interactions. Because of the reduced dimensionality, screening is hampered in 2D or quasi-1D materials, with important consequences in nanometer-scale systems that are currently important to the condensed matter community. This paper explains why reduced dimensionality reduces the screening. The topic is appropriate for undergraduate electromagnetism classes or advanced condensed matter courses. [ABSTRACT FROM AUTHOR]

Perovskites have long been materials of interest in solid‐state physics. Their structure leads them to exhibit various characteristics which have both theoretical and practical interest. Lattice dynamics can give a lot of insight into a material's nature such as phase transitions, thus the research presented here focuses on that, by doing a comprehensive vibrational and structural investigation of monocrystalline YAlO3 (YAP). Polarized Raman and infrared (IR) reflectance spectroscopy are used alongside ab initio and classical calculations. In the course of this work, complete Raman spectra have been obtained, confirming new vibrational modes, predicted by ab initio calculations but previously not observed experimentally. IR reflectance spectra have been obtained for the first time for this material. Classical molecular dynamics has been employed to calculate the phonon dispersion and density of states. [ABSTRACT FROM AUTHOR]

Optical vortex array (OVA) containing multiple optical vortices is an optimal candidate for applications of optical communications, complex manipulation of multi-particle systems, and mass-synchronous fabrication. However, the existing OVAs have not been constructed to respond to the application requirements, particularly for micro-/nanomaterial fabrication where the boundary, size, and stability need to be carefully considered. To address this issue, we propose a Gibbs–Wulff OVA (GWOVA) by analogizing the Gibbs–Wulff theorem in solid-state physics. Herein, the Gibbs–Wulff theorem is first generalized to OVA's generation as the condition to confine its growth boundary. The GWOVA, which possesses versatile structures and arrangement modes (simple- and close-packed modes), is successfully generated and grown. It exhibits high stability and perfect symmetry during growth and rotation, which satisfies the symmetric group of D2s. Owing to its stable structure and growth boundary conditions, the GWOVA has great potential for a wide range of applications, particularly in micro-/nanomaterial fabrication. [ABSTRACT FROM AUTHOR]

The solution of a quantum periodic potential in solid state physics is relevant because one can understand how electrons behave in a corresponding crystal. In this paper, the analytical solution of the energy formulation for a one-dimensional periodic potential that meets certain boundary conditions is developed in a didactic and detailed way. In turn, the group speed and effective mass are also calculated from the transcendental energy equation of a potential V = V (x) . From this, a comparison is made with periodic potentials with known analytical solutions, such as the Dirac delta, as well as rectangular and triangular potentials. Finally, some limits are proposed in which these periodic potentials of the form V = V (x) approach the periodic Dirac delta potential of positive intensity. Therefore, the calculations described in this paper can be used as the basis for more-complex one-dimensional potentials and related simulations. [ABSTRACT FROM AUTHOR]

Specific properties of quantum field theory are described by considering the combination of the system under investigation and the cloud of virtual or real particles associated with the field. Such a structure is called a "dressed system", in contrast with the bare one in the absence of the interaction with the field. The description of the properties of such clouds in various physical situations is, today, an active research area. Here, we present the main features associated with virtual and real dressings, focusing on photon dressing. In analogy to virtual photon clouds dressing electrons in vacuum, virtual phonon clouds appear in solid-state physics. The interaction between real photons and the schematized two-level structure of an atom paves the way to flexible quantum control. Here, a unifying Floquet engineering approach is applied to describe single- and multiple-dressed atom configurations. Connections with the past and present atomic physics experiments are presented. [ABSTRACT FROM AUTHOR]

I describe aspects of my life in physics: the name I publish under, great physicists I have known, how I got into quantum foundations, what role I've played in it. My form is autobiographical, but my personal experience may illustrate what it was like being a physicist over the past sixty years. I offer some offbeat ways of thinking about some orthodox physics. [ABSTRACT FROM AUTHOR]

The document titled "Advanced Inorganic Semiconductor Materials" is a summary of a special issue that explores current research and ideas in the field of inorganic semiconductors. The issue includes nine articles and two topical reviews that cover various topics, such as 2D materials, quantum dots, avalanche photodiodes, and perovskites. Each article delves into different aspects of these materials, including their optical, mechanical, and electronic properties, as well as their potential applications in optoelectronic devices. The findings presented in the articles contribute to the understanding and development of advanced inorganic semiconductor materials for various applications. The document expresses gratitude to the contributors and reviewers for their valuable contributions to the special issue. [Extracted from the article]

This review is devoted to one of the most interesting and actively developing fields in condensed matter physics—theory of topological insulators. Apart from its importance for theoretical physics, this theory enjoys numerous connections with modern mathematics, in particular, with topology and homotopy theory, Clifford algebras, K-theory and non-commutative geometry. From the physical point of view topological invariance is equivalent to adiabatic stability. Topological insulators are characterized by the broad energy gap, stable under small deformations, which motivates application of topological methods. A key role in the study of topological objects in the solid state physics is played by their symmetry groups. There are three main types of symmetries—time reversion symmetry, preservation of the number of particles (charge symmetry) and PH-symmetry (particle-hole symmetry). Based on the study of symmetry groups and representation theory of Clifford algebras Kitaev proposed a classification of topological objects in solid state physics. In this review we pay special attention to the topological insulators invariant under time reversion. [ABSTRACT FROM AUTHOR]

In the current research, we consider the solution of dispersion relations addressed to solid state physics by using artificial neural networks (ANNs). Most specifically, in a double semiconductor heterostructure, we theoretically investigate the dispersion relations of the interface polariton (IP) modes and describe the reststrahlen frequency bands between the frequencies of the transverse and longitudinal optical phonons. The numerical results obtained by the aforementioned methods are in agreement with the results obtained by the recently published literature. Two methods were used to train the neural network: a hybrid genetic algorithm and a modified version of the well-known particle swarm optimization method. [ABSTRACT FROM AUTHOR]

In this study, carbon fiber reinforced polymer matrix composites were produced to investigate the trigger effect on energy absorption performance. Production was carried out by vacuum infusion method. Three types of trigger geometry were opened on the composite crash boxes produced and also comparison sample without trigger was prepared. The quasi-static compression tests of these four different samples were carried out and the energy absorption performances of the samples were evaluated with the obtained data. In addition, the damages of the samples were examined, and it was revealed how they changed with the trigger. Accordingly, the sample described as S-2, (the triggered sample, which consists of four symmetrical slits downwards from its upper surface) exhibited the best performance in terms of absorbed energy. Additionally, the peak forces were reduced with the triggers opened and the maximum peak force decreases were seen in S-3(with hole type triggers) and S-4 (with horizontal slit type triggers) samples. [ABSTRACT FROM AUTHOR]

SUMMARY OF COVERED AREAS Several articles in this special topics issue focus on the location of solid-fluid phase equilibria lines, using either simulation,[[17], [19], [21], [23]] theoretical,[21] or experimental methods.[24] Knowledge of coexistence lines is obviously interesting on its own right, but several articles highlight other reasons why precise knowledge of phase equilibria is relevant. Obtaining a deep knowledge of the behavior of condensed phases (solids, liquids, and amorphous) is a great challenge. This challenge is compounded in studies in which two or more phases need to be described simultaneously, for example, in the characterization of solid-liquid interfaces or the prediction of solid-liquid phase equilibrium. [Extracted from the article]

The article focuses on the Nobel Prize in Chemistry 2023 awarded to Aleksey Yekimov, Louis E. Brus, and Moungi G. Bawendi for their discovery and synthesis of quantum dots. Topics include the history of quantum size effects, the pioneering experiments in the 1970s, the independent work of Yekimov and Brus in the 1980s, and the subsequent breakthroughs by Bawendi in the 1990s, leading to the widespread applications of quantum dots in scientific research and commercial products.

The well-established and rapidly expanding field of molecular processes in excited systems, facilitated by the use of light sources, garners significant research interest from numerous experimental and theoretical groups worldwide. This highly interdisciplinary field establishes extensive connections with atomic, molecular and optical physics, astrophysics, biophysics, physical chemistry, solid-state physics and even molecular biology. The present topic provides an advanced overview of research activities in cutting-edge areas such as ultrafast lasers, nanoscale systems, atomic and molecule collisions on surfaces and molecular photofragmentation processes. The contributions to this subject encompass experimental, theoretical and computational studies conducted both at the fundamental level, exploring elementary mechanisms, and at a more applied level, addressing the requirements of diverse applications in nanotechnology and materials science. [ABSTRACT FROM AUTHOR]

This paper concerns the homogenization of Schrödinger equations for non-crystalline matter, that is to say the coefficients are given by the composition of stationary functions with stochastic deformations. Two rigorous results of so-called effective mass theorems in solid state physics are obtained: a general abstract result (beyond the classical stationary ergodic setting), and one for quasi-perfect materials (i.e. the disorder in the non-crystalline matter is limited). The former relies on the double-scale limits and the wave function is spanned on the Bloch basis. Therefore, we have extended the Bloch Theory which was restricted until now to crystals (periodic setting). The second result relies on the Perturbation Theory and a special case of stochastic deformations, namely stochastic perturbation of the identity. [ABSTRACT FROM AUTHOR]

Peierls transition that modifies electronic band structure has attracted intensive attention in solid state physics. In the present work, we report that a photonic analog of Peierls transition has been observed in a 1-D triangular metal diaphragm array, where the photonic bandgap structures have been designed at will by adjusting periodically metal diaphragm positions. It is shown by the numerical analysis that the transmission and radiation effect of the present periodic metal structure designed through the Peierls transition rule exhibits the behavior significantly different from an original periodic structure with each unit cell containing a metal diaphragm. The near- and far-field measurement results are in good agreement with our theoretical simulation. The present effect of photonic Peierls transition can serve as a working mechanism for designing new types of guided wave devices. It can be seen that the photonic Peierls transition would be one of the simplest ways for modifying the transport characteristics of electromagnetic waves in periodic structures. [ABSTRACT FROM AUTHOR]

Tavis-Cummings (TC) cavity quantum electrodynamical effects, describing the interaction of N atoms with an optical resonator, are at the core of atomic, optical and solid state physics. The full numerical simulation of TC dynamics scales exponentially with the number of atoms. By restricting the open quantum system to a single excitation, typical of experimental realizations in quantum optics, we analytically solve the TC model with an arbitrary number of atoms with linear complexity. This solution allows us to devise the Quantum Mapping Algorithm of Resonator Interaction with N Atoms (Q-MARINA), an intuitive TC mapping to a quantum circuit with linear space and time scaling, whose N+1 qubits represent atoms and a lossy cavity, while the dynamics is encoded through 2N entangling gates. Finally, we benchmark the robustness of the algorithm on a quantum simulator and superconducting quantum processors against the quantum master equation solution on a classical computer. [ABSTRACT FROM AUTHOR]

The quantum Hall effect is one of the most extensively studied topological effects in solid‐state physics. The transitions between different quantum Hall states exhibit critical phenomena described by universal critical exponents. Numerous numerical finite size scaling studies have focused on the critical exponent ν for the correlation length. In such studies, it is important to take proper account of irrelevant corrections to scaling. Recently, Dresselhaus et al. proposed a new scaling ansatz, which they applied to the two terminal conductance of the Chalker–Coddington model. Herein, their proposal is applied to the previously reported data for the Lyapunov exponents of that model using both polynomial fitting and Gaussian process fitting. [ABSTRACT FROM AUTHOR]

The interest in RBa2Cu3O7–δ (R = lanthanides) stems from its superconducting properties. These represent a very significant advance in solid-state materials physics and have been extensively studied for decades, with the aim of increasing the critical temperature by doping or external parameters such as pressure. In the present review, we briefly discuss oxygen diffusion in RBa2Cu3O7–δ with respect to its composition. We consider related compounds as a comparison. [ABSTRACT FROM AUTHOR]

We consider a connection problem of the first Painlev\'e equation (PI), trying to connect the local behavior (Laurent series) near poles and the asymptotic behavior as the variable t tends to the negative infinity for real PI functions. We get a classification of the real PI functions in terms of (p, H) so that they behave differently at the negative infinity, where p is the location of a pole and H is the free parameter in the Laurent series. Some limiting-form connection formulas of PI functions are obtained for large H. Specifically, for the real tritronqu\'ee solution, the large-n asymptotic formulas of pn and Hn are obtained, where pn is the nth pole on the real line in the ascending order and Hn is the associated free parameter. Our approach is based on the complex WKB method (also known as the method of uniform asymptotics) introduced by Bassom et al. in their study on the connection problem of the second Painlev\'e transcendent [Arch. Ration. Mech. Anal., 143 (1998), pp. 241--271]. Several numerical simulations are carried out to verify our main results. Meanwhile, we obtain the phase diagram of P\I solutions in the (p, H) plane, which somewhat resembles the Brillouin zones in solid-state physics. The asymptotic and numerical results obtained in this paper partially answer Clarkson's open question on the connection problem of the first Painlev\'e transcendent. [ABSTRACT FROM AUTHOR]

Introductory textbooks in solid state physics present solvable models for illustrating the occurrence of allowed bands and forbidden gaps in the energy spectrum of Bloch electrons. However, the quantum mechanical description of electrons in non-periodic solids, such as amorphous materials, is beyond the scope of introductory courses because of its intrinsic complexity. The tight-binding approximation can account for such a scenario by letting the atomic levels vary at random from lattice site to site. We theoretically tackle the study of the average properties of the energy spectrum by introducing a transfer matrix method that allows us to obtain closed expressions for the so-called coherent potential. The coherent potential is energy-dependent and constant in space. It replaces the actual atomic random potential, thus generating a periodic effective medium with the same average properties as the non-periodic solid. We demonstrate that the average density of states can be calculated within this framework without relying on heavy mathematical machinery. Thus, our approach is suitable for introductory courses in solid state physics and materials science. [ABSTRACT FROM AUTHOR]

Introduction/purpose: Quantum field theory techniques are able to describe precisely, inter alia, collective phenomena of statistical and solid state physics. Method: The path integral method with a Wick rotation shows its complete analogy with the partition function of statistical mechanics. Results: The Landau–Ginzburg phenomenology successfully describes collective phenomena such as spontaneous magnetization and superconductivity. Conclusions: Symmetry breaking phenomena could give macroscopic results. [ABSTRACT FROM AUTHOR]

There are opportunities for the application of chemical physics style thinking to models central to solid state physics. Solid state physics has largely been left to its own devices by the chemical physics theory community, which is a shame. I will show here that cross fertilization of ideas is real and beneficial to science. This essay is written with the hope of encouraging young theorists with a chemical physics background to enter this rich and promising area. There are many low hanging fruit available essentially because condensed matter physics traditions, models, and standards for progress are so much different than in chemical physics. By way of a warning label, right now neither community is supporting this endeavor. I am hoping this article will help, a little. I make the apology for using mainly (but not exclusively) my own narrow experience and contributions to illustrate this essay. I understand it is only a small piece of the pie, but I do believe the message here is larger: a chemical physics mindset is complementary to the condensed matter physics mindset, and they would work best together. [ABSTRACT FROM AUTHOR]

Peierls transition that modifies electronic band structure has attracted intensive attention in solid state physics. In the present work, we report that a photonic analog of Peierls transition has been observed in a 1-D triangular metal diaphragm array, where the photonic bandgap structures have been designed at will by adjusting periodically metal diaphragm positions. It is shown by the numerical analysis that the transmission and radiation effect of the present periodic metal structure designed through the Peierls transition rule exhibits the behavior significantly different from an original periodic structure with each unit cell containing a metal diaphragm. The near- and far-field measurement results are in good agreement with our theoretical simulation. The present effect of photonic Peierls transition can serve as a working mechanism for designing new types of guided wave devices. It can be seen that the photonic Peierls transition would be one of the simplest ways for modifying the transport characteristics of electromagnetic waves in periodic structures. [ABSTRACT FROM AUTHOR]

This paper addresses semiconductor piezoresistive materials selection in MEMS engineering design. From the practical engineering point of view, it is important to understand piezoresistance properties of semiconductors even if less accuracy under feasibility design phase. However, piezoresistance is frequently analyzed based on first principle electronic band structure simulations by sophisticate physicists. Practical engineers not familiar with this simulation cannot directly apply useful information derived from the result of simulation. This paper provides practical prediction method for piezoresistance based on electronic band parameters obtained from the state‐of‐the‐art solid‐state physics. It is demonstrated that the crucial parameters which control the p‐type shear piezoresistance coefficient π44 in diamond and zinc‐blend single crystals are the inverse of square of bond length in unit cell atom, the square root of valence light hole mass, and the shear elastic compliance coefficient S44. [ABSTRACT FROM AUTHOR]

The quantum Hall effect is widely used for the investigation of fundamental phenomena, ranging from topological phases to composite fermions. In particular, the discovery of a room temperature resistance quantum in graphene is significant for compact resistance standards that can operate above cryogenic temperatures. However, this requires large magnetic fields that are accessible only in a few high magnetic field facilities. Here, we report on the quantum Hall effect in graphene encapsulated by the ferroelectric insulator CuInP2S6. Electrostatic gating of the graphene channel enables the Fermi energy to be tuned so that electrons in the localized states of the insulator are in equilibrium with the current-carrying, delocalized states of graphene. Due to the presence of strongly bound states in this hybrid system, a quantum Hall plateau is observed over a wide range of temperatures in relatively modest magnetic fields. The quantum Hall effect has had a profound impact on solid-state physics and has been investigated using different two-dimensional systems, including graphene. Here, the authors investigate graphene encapsulated by a ferroelectric insulator, CuInP2S6, where they observe a quantum Hall effect that endures over a wide temperature range in relatively modest magnetic fields. [ABSTRACT FROM AUTHOR]

The Allen–Cahn equation (ACE), which has applications in solid-state physics, imaging, plasma physics, material science and other fields, is one of the most important models of the modern era for describing the dynamics of oil pollution, reaction-diffusion mechanisms, and the mechanics of crystalline solids. By using the (1 G ′ ) -expansion method (GEM) and the Bernoulli sub-ODE schemes, some new traveling wave solutions for the governing model are created in this study (BSODE). The reduced integrable ordinary differential equation is produced using the traveling wave hypothesis. To better understand their behavior, the 3D, contour, and 2D graphs are displayed for a number of fascinating exact solutions. Additionally, we use numerical simulation to confirm the stability of the derived analytical solutions. It results the propagation of temporal soliton for long time of simulation. These results will be used to explain physical phenomenon in crystalline solids and others fields. [ABSTRACT FROM AUTHOR]

Traditional solid-state physics has long correlated the optical properties of materials with their electronic structures. However, recent discoveries of intrinsic gapped metals have challenged this classical view. Gapped metals possess electronic properties distinct from both metals and insulators, with a large concentration of free carriers without any intentional doping and an internal bandgap. This unique electronic structure makes gapped metals potentially superior to materials designed by intentional doping of the wide bandgap insulators. Despite their promising applications, such as transparent conductors, designing gapped metals for specific purposes remains challenging due to the lack of understanding of the correlation between their electronic band structures and optical properties. This study focuses on representative examples of gapped metals and demonstrates the cases of (i) gapped metals (e.g., CaN2) with strong intraband absorption in the visible range, (ii) gapped metals (e.g., SrNbO3) with strong interband absorption in the visible range, and (iii) gapped metals (e.g., Sr5Nb5O17) that are potential transparent conductors. We explore the complexity of identifying potential gapped metals for transparent conductors and propose inverse materials design principles for discovering next-generation transparent conductors. [ABSTRACT FROM AUTHOR]

The Tzitzéica equation, the Dodd–Bullough–Mikhailov equation, and the Tzitzéica–Dodd–Bullough equation arise in various branches of science and technology, such as solid state physics, nonlinear dynamics, nonlinear optics, and quantum field theory problems. In this paper, we discuss how to find more general wave solutions of these three nonlinear evolution equations with physical applications using the unified method. The unified method straightforwardly gives many more general solutions with free parameters without the need for extra hardware support. After performing calculations, the graphs of the solutions are plotted using Maple to give insight into the physical structure of the wave solution. Only some selected solutions are plotted to visualize their behavior. Considering the importance of having solutions for nonlinear wave phenomena, we clearly see that the method has many merits and demonstrates a comprehensive application to obtaining solutions in an efficient way. In addition, diverse types of geometrically structured solitons such as an anti-bell-shaped soliton, a flat soliton, a kink, and a singular soliton are produced by using arbitrary parameters. [ABSTRACT FROM AUTHOR]

Solid state ionics is one of the key research topics of the Institute of Solid State Physics, University of Latvia since its establishment. The research direction included topics ranging from electrochromic phenomena in transition metal oxides through gas sensors and electronic nose to materials for rechargeable battery electrodes and materials for hydrogen energy. By the late 1980s, the institute had become one of the biggest and most prolific solid state ionic centres in the USSR and Eastern Europe and continues to maintain its position among the regional leaders in the field. Regular regional conferences and workshops were organized and some of the published works can be ranked among the pioneering works in the world of science. This extensive historical review summarizes information on the development of solid state ionics, actual research and achievements from establishment of the institute to the present day. Currently many collaborations are ongoing with partners across Europe and beyond in research ranging from battery materials and smart windows for zero energy buildings to hydrogen production, maintaining and growing its strength as key national, regional, and international centre of research excellence in solid state ionics. [ABSTRACT FROM AUTHOR]

Point-contact spectroscopy offers a unique straightforward possibility to study the electronic properties of metals. Soon after the invention of this technique by Igor Yanson in the B. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine [Sov. Phys. JETP39, 506 (1974)], multiple laboratories adopted this technique and applied it to various topical problems in modern solid-state physics. Here, we offer a brief review of how point-contact spectroscopy has been developed and used in the Centre of Low Temperature Physics Košice. By this technique, we were able to obtain for example the spectrum of the electron-phonon interaction in an unprecedented large energy scale up to 160 meV in LaB6. The Zeeman splitting of the Pr3+ ion levels in the crystal-electric field has been detected for the first time in PrNi5. "Inverse" point-contact spectra of the electron-phonon interaction found in semimetallic arsenic were explained by the weak localization in the point-contact area. The point-contact Andreev reflection spectroscopy enabled to detect not only the superconducting energy gap in YB6, but also the Einstein-like phonon mode responsible for superconductivity. The first spectroscopic evidence of the two-gap superconductivity in MgB2 has been provided in our experiments. High spin polarization in Co2FeSn Heusler nanowires for spintronics has been obtained. [ABSTRACT FROM AUTHOR]

Crystal structure predictions based on first-principles calculations have gained great success in materials science and solid state physics. However, the remaining challenges still limit their applications in systems with a large number of atoms, especially the complexity of conformational space and the cost of local optimizations for big systems. Here, we introduce a crystal structure prediction method, MAGUS, based on the evolutionary algorithm, which addresses the above challenges with machine learning and graph theory. Techniques used in the program are summarized in detail and benchmark tests are provided. With intensive tests, we demonstrate that on-the-fly machine-learning potentials can be used to significantly reduce the number of expensive first-principles calculations, and the crystal decomposition based on graph theory can efficiently decrease the required configurations in order to find the target structures. We also summarized the representative applications of this method on several research topics, including unexpected compounds in the interior of planets and their exotic states at high pressure and high temperature (superionic, plastic, partially diffusive state, etc.); new functional materials (superhard, high-energy-density, superconducting, photoelectric materials), etc. These successful applications demonstrated that MAGUS code can help to accelerate the discovery of interesting materials and phenomena, as well as the significant value of crystal structure predictions in general. [ABSTRACT FROM AUTHOR]

Developing predictive thermal property models for liquids based on microscopic principles has been elusive. The difficulty is that liquids have gas-like and solid-like attributes that are at odds when considering the frameworks of microscopic models: Models for gases are simple due to randomness and low density, whereas models for crystalline solids rely on symmetry and long-range order for easier calculation. The short-range order in liquids does, however, provide structure to neighboring molecules similar to amorphous solids, and there have been recent advances indicating that collective vibrational modes store heat in liquids. Models combining Debye approximations from solid-state physics and Frenkel's theory of liquids can accurately predict the heat capacity of liquids. Phonon-like dispersions in liquids have also been widely observed in neutron scattering experiments. These developments motivate us to propose a model where high-frequency vibrational modes, which travel at the speed of sound and have a mean free path on the order of the average intermolecular distance, conduct heat in liquids. We use this liquid phonon gas model to calculate the thermal conductivity of liquids with varying intermolecular interaction energies from strongest to weakest—Coulomb, hydrogen-bonding, Keesom, and London dispersion energy. Generally, the model is more accurate as the intermolecular interaction energy and density of liquids increase. The calculated thermal conductivity of Coulombic-bound molten sodium nitrate and hydrogen-bonded water is within 1.46% and 2.98% of the experimentally measured values, respectively, across their entire temperature ranges. Further modal analysis of the velocity and the mean free path of collective vibrations could establish the liquid phonon gas model as an accurate model for weakly interacting liquids as well. [ABSTRACT FROM AUTHOR]

Radii Mykolayovych Gurzhi was a renowned scientist who made significant contributions to the field of solid-state physics, particularly in the theory of kinetic phenomena in metals and dielectrics. His work included the development of the theory of high-frequency properties of metals, the derivation of the quantum kinetic equation, and the theory of hydrodynamic effects in metals, dielectrics, and semiconductors. He also made contributions to the understanding of low-temperature electrical conductivity in pure metals and the study of low-dimensional conductors. Additionally, Gurzhi worked in the field of spintronics, where he predicted spin dynamics effects in magnetically non-uniform conducting systems. His theoretical predictions often preceded experimental confirmation and continue to be relevant in contemporary research. This collection of papers in the journal Low Temperature Physics explores topics related to Gurzhi's pioneering contributions, including electron hydrodynamics and kinetics in low-dimensional systems. [Extracted from the article]

An essay on the 100-year history of the formation and development of the Department of X-ray Diffraction Analysis, subsequently transformed into the Department of Solid State Physics of the Faculty of Physics of Moscow State University, is presented. [ABSTRACT FROM AUTHOR]

The results of the Mössbauer spectroscopy studies in the field of mechanochemical synthesis of functional composites, carried out for more than 25 years at Moscow State University (Faculty of Physics, Department of Solid State Physics) and at the Institute of Solid-State Chemistry and Mechanochemistry of the Siberian Branch of the Russian Academy of Sciences (Laboratory of Chemical Materials Science), are reviewed. [ABSTRACT FROM AUTHOR]

This paper investigates the performance of soft barriers installed in the ground for screening shear and compression waves in saturated and dry grounds. The proposed barriers include the soil as a core surrounded by a soft material like foam. The barriers are arranged in periodic structures, and it is aimed to find their bandgaps using solid-state physics theories. Firstly, an ideal infinite lattice is considered, and its bandgaps and attenuation zones are found using Bloch–Floquet theory. Thereafter, a finite lattice of barriers is also investigated for practical purposes, and the minimum required number of barrier rows to obtaining similar bandgaps is obtained. The infinite and finite lattices are simulated using finite element COMSOL Multiphysics software with its inbuilt features. Also, the analyses are performed in dry and saturated grounds using elastodynamic and Biot's poroelastodynamic theories, respectively. Extensive parametric studies are also conducted on the material and geometric properties of the barriers, and the corresponding bandgap properties are discussed. The finite element simulations are performed in both frequency and time domains. The obtained results indicate the effectiveness of using soft barriers around the soil in a unit cell for screening the waves in dry and saturated grounds. [ABSTRACT FROM AUTHOR]

At the same time, Lev Blinov maintained a close interaction with the LC laboratory at the Institute of Crystallography in Moscow and actively participated in the work on lasing in LCs. The results of the studies on LCs were summarised in Blinov's first monograph "Electrooptical and magnetooptical properties of liquid crystals" issued by the Moscow Publisher "Nauka" in 1978. In Blinov's laboratory work was carried out on anchoring energy studies of nematic LCs with substrates, various electro-optical effects and the "guest-host" effect in LCs with dichroic dyes. Since the mid-1980s, Lev Blinov became deeply involved in the physics of LC surfaces and studies of the anchoring energy I W i of nematic LCs within confining substrates. [Extracted from the article]

The invention of superconductivity was a major advance of solid state physics. In the present review, we briefly discuss the emergence of RBa2Cu3O7–δ (R are lanthanides). In the first part, we consider the impact of lanthanide doping and the intricacy of the praseodymium anomaly. In the second part, we discuss the impact of external parameters such as pressure and electron irradiation on the critical superconducting parameters. This brief review concludes with future perspectives of the field, considering recent advances. [ABSTRACT FROM AUTHOR]

An explicit expression relating the magnitude of the fifth-order off-diagonal cusp in the real part of the one-electron reduced density matrix to the "on-top" two-electron density is derived in a rigorous manner from the behavior of the underlying electronic wavefunction at the electron–electron coalescence. The implications of the presence of this cusp upon electronic structure calculations of quantum chemistry and solid-state physics, including the limits imposed upon their accuracy, are elucidated. In particular, the power-law decay of the occupation numbers of the natural orbitals is demonstrated for 1S states of systems composed of arbitrary even numbers of electrons. The practical importance of analogous off-diagonal cusps in many-electron reduced density matrices is briefly discussed. [ABSTRACT FROM AUTHOR]

The May 2024 issue of the American Journal of Physics features a variety of articles covering topics in physics. These include letters to the editor, a tool for developing inclusive physics textbooks, labor-based grading practices, a modern interpretation of Newton's theorem of revolving orbits, the effects of general relativistic post-Newtonian approximations, seldom-used theorems of vector calculus, screening in solid state physics, the hyperfine interaction in hydrogen, the Born rule in quantum mechanics, statistical physics of frictional grains, an in-fiber Mach-Zehnder strain sensor, an Arduino cavity controller for LIGO analogy lab, a resolution of the trolley paradox, an unorthodox physical solution to a classic puzzle, and a book review on solar power finance. These articles cover a range of topics and can be useful for researchers and students in various physics disciplines. [Extracted from the article]