ABSTRACT To investigate the photoresponse of metal‐ferroelectric‐metal (MFM) devices, we sandwich polycrystalline bismuth ferrite between two electrodes of similar work function. We use calcium‐substitution on the A‐site to tailor the properties of bismuth ferrite Bi 1‐x Ca x FeO 3‐δ from ferroelectric ( x < 0.2) to nonferroelectric ( x > 0.2). Devices with nonferroelectric Bi 1‐x Ca x FeO 3‐δ show symmetric current density‐voltage ( J–V ) curves and no photoresponse, resembling their symmetric electronic properties that originate from two opposing Schottky junctions at the symmetric electrodes. In contrast, the J–V curves of ferroelectric Bi 1‐x Ca x FeO 3‐δ are governed by the polarization direction, introducing directionality through modification of the Schottky barriers. Under illumination, the polarization induced modulation of the Schottky barriers promotes directionality of the photogenerated charge carriers and leverages enhanced photocurrents.
ABSTRACT Ferroelectric field‐effect transistors have emerged as promising device platforms for next‐generation electronics due to their ability to combine nonvolatile memory operation with polarization‐controlled modulation of channel conductance. Recent research has extended ferroelectric field‐effect transistors (FeFETs) beyond their traditional use as memory transistors to multifunctional hardware which allows optoelectronic signal processing, neuromorphic operation, and in‐memory computing. This paper covers current developments in FeFETs from the perspectives of ferroelectric materials, device architectures, integration platforms, and neuromorphic applications. First, we go over representative ferroelectric material systems used in FeFETs, such as HfO 2 ‐based ferroelectrics, two‐dimensional ferroelectric materials, and organic ferroelectrics with a focus on how these systems affect device physics, scalability, and functional variety. Next, we discuss interface engineering in FeFETs and examine FeFET‐based memory architectures and structural platforms, emphasizing silicon‐based and flexible implementations as well as vertically integrated 3D FeNAND arrays. We also discuss reliability and degradation issues in FeFETs, and this review further highlights the increasing number of applications of FeFETs in neuromorphic computing, such as analog synaptic devices, leaky integrate‐and‐fire neurons, optoelectronic synaptic behaviors, associative learning, and reservoir computing. Overall, FeFETs are developing from nonvolatile memory devices into multifunctional platforms that can connect computation, memory, and sensing in small, energy‐efficient systems.
It is known that the attractive singular inverse-square potential gives rise to the critical quantum collapse in the framework of the three-dimensional (3D) linear Schroedinger equation. This article summarizes theoretical results which demonstrate suppression of the collapse, caused by this singular potential, and the creation of the otherwise missing ground state (GS) in a 3D gas of bosonic particles, carrying an electric dipole moment, which are pulled to the central electric charge, with repulsive contact interactions between the particles. In the mean-field approximation, the repulsive interactions are represented by the cubic term in the respective Gross-Pitaevskii (GP) equation. In addition to the GS, excited states with angular momentum are briefly considered too. Another topic considered in the article is 1D and 2D bound states in the linear Schroedinger and GP equations with the repulsive potential, which demonstrates a singularity at r –> infinity. A very recent result is that such a potential, growing faster than the negative harmonic-oscillator potential, produces a full spectrum of counter-intuitive normalizable (localized) bound states. The article puts forward perspectives for further studies of linear and nonlinear bound states existing under the action of the potentials with the singularity at r –> 0 or r –> infinity.
ABSTRACT In this study, a new semiconducting material, InPSi 3 , has been explored using density functional theory (DFT) calculations, along with an investigation of the unexplored properties of the newly predicted AlPSi 3 and GaPSi 3 semiconductors. The negative formation energy, elastic constants, and positive phonon modes certify the stability of all three compounds. InPSi 3 is an indirect‐band‐gap semiconductor (1.58 eV), whereas AlPSi 3 and GaPSi 3 are direct band gaps with an E g of 1.64 and 1.51 eV, respectively. We used DOS to investigate the nature of bonding. Additionally, optical coefficients, including the dielectric constant, refractive index, extinction coefficient, photoconductivity, optical absorption, reflectivity, and loss function, were computed. The mechanical behavior was studied by calculating elastic constants, elastic moduli, and brittleness indices. The thermal parameters, including Debye temperature, melting temperature, thermal conductivity, minimum thermal conductivity, thermal expansion coefficient, and specific heat capacity, have been investigated. The thermoelectric properties, including electrical conductivity ( σ / τ ), electronic thermal conductivity ( K e / τ ), Seebeck coefficient (S), power factor (PF), and figure of merit (ZT), were calculated. The titled materials would be appropriate for individual solar cells or the top portion of tandem solar cells, owing to their appropriate band gap and optical absorption.
ABSTRACT Defect diamond‐like chalcogenides have emerged as an important class of infrared nonlinear optical (IRNLO) materials because they can combine strong second‐harmonic generation, structural flexibility, and useful optical transparency. In this work, the structural, electronic, vibrational, optical, elastic, and thermal transport properties of Hg3P2S8 (HPS) were systematically investigated using first‐principles calculations based on density functional theory and density functional perturbation theory. The results show that HPS is a direct‐band‐gap semiconductor with a bandgap of 1.906 eV. Phonon‐dispersion calculations reveal the absence of imaginary modes, confirming the dynamical stability of the crystal. Raman analysis identifies the characteristic vibrations of the distorted HgS4 and rigid PS4 tetrahedral units, which are key to the defective diamond‐like framework. Optical calculations indicate a strong ultraviolet response, with pronounced reflectivity, absorption, dielectric activity, optical conductivity, and energy‐loss features concentrated in the short‐wavelength region. HPS is a relatively soft, anisotropic material (BH = 16.067 GPa, GH = 10.279 GPa, E = 25.416 GPa) with a low acoustic Debye temperature (170 K) and intrinsically low lattice thermal conductivity (0.993–0.298 W m−1 K−1 from 300–1000 K). These findings provide a comprehensive structure–property understanding of HPS and highlight promise for IR‐NLO, optoelectronic, and photonic applications.
ABSTRACT The LaAlO 3 /SrTiO 3 (LAO/STO) interface is a vital platform for emergent quantum phenomena, yet conventional methods for controlling its properties are often invasive. This work introduces supercritical CO 2 (SC CO 2 ) as a clean, tunable “physical strain field” to achieve a reversible diamagnetic‐to‐ferromagnetic transition in 3D LAO/STO composite powders via pressure tuning. Structural analysis reveals that under specific conditions (100°C, 14 MPa), SC CO 2 induces a tensile strain along the c‐axis in LAO. This strain is coupled through the coherent interface to the STO lattice, leading to cooperative lattice distortion without introducing significant chemical defects. Magnetic measurements confirm that the emergent ferromagnetism originates strictly from the interface and is precisely correlated with this unique lattice strain condition. This work unveils a new mechanism of interfacial lattice strain‐driven ferromagnetism and establishes a novel, non‐destructive paradigm for tuning quantum states at complex oxide interfaces using supercritical fluids.
ABSTRACT Proteinoid‐ nanoparticle composites are a new hope in unconventional computing. They use self‐assembling protein‐like polymers along with the magnetic and electronic traits of iron oxide nanoparticles. This study looks at how Glu‐Phe‐Asp proteinoid microspheres work with nanoparticles. It shows their potential for use in neuromorphic computing. We found spontaneous electrical oscillations in these composites. We also looked at how external magnetic fields (65, 84, and 103 mT) change their oscillatory behavior. Our findings reveal that these composites can emulate Boolean logic gates, with distinct responses to varying magnetic field strengths. nanoparticles boost the proton‐driven spiking in proteinoid microspheres. This leads to adjustable electrochemical behavior. This work shows that proteinoid‐ nanoparticle composites can be a great platform. They can help create bio‐inspired computing systems. These systems may have adaptive functions, save energy, and resist faults. This opens new doors for neuromorphic systems that imitate biological neural networks.
ABSTRACT This review introduces a quantitative decision‐making framework based on the Lindblad master equation and the formalism of open quantum systems. This framework facilitates the identification of phenomena within molecular and biological systems that require explicit quantum‐mechanical analysis beyond classical approximations. It does not merely reiterate that quantum mechanics underpins all chemical processes; rather, this principle serves as a foundational premise rather than an original contribution. The significant contribution consists of a set of operational criteria derived from decoherence timescales, conditions for Markovian validity, boundaries of the computational domain, and requirements for experimental falsifiability. These criteria enable physicists or physical chemists to assess, for any molecular system and quantum hypothesis, whether the hypothesis is supported by evidence, remains speculative, or can be falsified through targeted experimentation. Three quantitative deliverables implement this framework. First, the τ dec > τ func condition is derived from the Lindblad formalism and applied numerically to each class of biological quantum phenomenon: enzyme hydrogen tunneling satisfies the condition by approximately one order of magnitude (τ transit ≈ 0.1 femtoseconds vs. τ dec ≈ 1 femtosecond in a hydrophobic active site); the radical pair mechanism satisfies it by one to fourteen times (τ dec 1 to 10 microseconds vs. τ func ≈ 710 nanoseconds at geomagnetic field strength); photosynthetic electronic coherence operates in the non‐Markovian regime where the Lindblad equation fails and the τ dec /τ func ratio is marginal. Second, a failure‐mode taxonomy is defined in Section 2 as the primary methodological tool: five criteria and a set of operationally testable red flags, applied as a running template to every phenomenon section throughout the review. Third, specific quantitative predictions are derived for each contested phenomenon, stating the observable, the predicted effect magnitude, and the control experiment distinguishing quantum from classical mechanisms. Quantum chemistry methods, including Density Functional Theory (DFT), Quantum Mechanics/Molecular Mechanics (QM/MM), and Fragment Molecular Orbital (FMO) techniques, are assessed within their rigorously validated accuracy domains. The approximately 1 kcal/mol accuracy of hybrid DFT applies to closed‐shell main‐group organic systems but does not extend to transition‐metal complexes, open‐shell species, or a broad range of pharmaceutical chemicals without explicit benchmarking. This limitation is consistently applied throughout the review and is not relaxed in discussions of applications. Kinetic isotope effects that surpass the zero‐point‐energy‐corrected semiclassical limit of approximately 6.9 at 298 K exemplify nuclear tunneling phenomena in enzymatic catalysis. In drug design, deuterium isotope substitution exploits this effect through empirical substitution strategies rather than quantum tunneling calculations; these contributions are distinct and should not be conflated. Quantum computing satisfies the τ dec > τ func condition at the single‐gate level but fails to meet the requirements at the circuit depth necessary for fault‐tolerant molecular simulation without error correction.
ABSTRACT Magnetocaloric materials receive considerable attention as promising candidates for next‐generation energy‐efficient and environmentally benign solid‐state refrigeration technologies. These materials exhibit the magnetocaloric effect (MCE), whereby heat is absorbed or released upon the application or removal of a magnetic field. In this study, the magnetocaloric properties of compounds TbMn 2‐x Ti x Si 2 (0.1 ≤ x ≤ 0.3) are systematically investigated. The series exhibits a substantial magnetocaloric response and large refrigerant capacities, rendering them attractive for low‐temperature cooling applications. Comprehensive structural and magnetic characterizations are conducted using temperature‐dependent neutron diffraction, magnetization measurements, and specific heat analysis. The substitution of Ti for Mn leads to a noticeable expansion of the unit cell and induces pronounced modifications in the magnetic transition behavior. Notably, the two first‐order ferromagnetic transition temperatures progressively decrease with increasing Ti content, shifting from T C1 = 50 K and T C2 = 62 K for x = 0.0 to T C1 = 37 K and T C2 = 44 K for x = 0.3. These results underscore of magnetic phase transitions and MCE performance through chemical substitution, reinforcing the potential of Ti‐doped TbMn 2‐x Ti x Si 2 compounds for low‐temperature magnetic refrigeration applications.
Spin-charge interconversion in ferromagnetic metals provides an unconventional pathway to explore spin-orbit coupling beyond heavy nonmagnetic systems. While ferromagnetic Ni80Fe20 has long been regarded as a spin source, its role as a spin-current detector remains largely unexplored. Here, we demonstrate the direct detection of a pure inverse spin Hall effect (ISHE) in a Ni80Fe20 layer interfaced with a ferrimagnetic insulator, yttrium iron garnet (Y3Fe5O12, YIG). A thermally generated spin current produced by the longitudinal spin Seebeck effect (LSSE) in YIG is converted into a transverse charge voltage within the Ni80Fe20 layer. Importantly, systematic control experiments using Ni80Fe20/Al2O3 bilayers, combined with symmetry-controlled measurement geometries, quantitatively eliminate anomalous Nernst contributions, thereby establishing that the observed voltage originates intrinsically from the ISHE in ferromagnetic Ni80Fe20. These findings identify ferromagnetic metals as viable spin-current detectors and provide a conceptually simple platform for investigating spin-orbit interactions and spin caloritronic phenomena without relying on heavy nonmagnetic metals.
This study presents a mathematical framework to analyze the transmission dynamics of an amoeba-induced central nervous system infection. The population is divided into compartments including susceptible, exposed, infected, quarantined, hospitalized, recovered, protected, and deceased. A system of nonlinear ordinary differential equations models disease progression and intervention effects. The models qualitative behavior is examined through equilibrium analysis. The disease-free equilibrium is derived, and its local and global stability are established using the Jacobian matrix, Lyapunov function, and LaSalles invariance principle. The basic reproduction number is identified as a key threshold governing disease extinction or persistence. Due to nonlinearity, numerical solutions are obtained using the fourth-order Runge Kutta method and an artificial neural network approach. Comparative analyzes based on error metrics, regression, and correlation measures show strong agreement between both methods. The results validate the model and demonstrate the effectiveness of neural networks for solving complex epidemic systems.
ABSTRACT The role of long‐range interactions in topological quantum systems is reviewed with emphasis on the long‐range p‐wave superconductor and its variants. Basic concepts of the lattice model with couplings decaying by power law of distance are introduced to frame the underlying theoretical formalism. This review centers on properties of the long‐range phase that finds no counterpart in the short‐range limit. The breakdown of conformal symmetry in critical regimes and the appearance of massive edge modes differing from conventional Majorana zero modes are discussed. Relevant features including the fractional topological invariant, violations of the area law, and anomalous transport characteristics are also described. Theoretical studies of realistic condensed‐matter realizations such as helical Shiba chains, hybrid nanowires, and other platforms are covered to assess their feasibility under various experimental constraints. Finally, experimental efforts are surveyed where implementations in solid‐state devices and other systems that can simulate effective long‐range topological Hamiltonians are both highlighted.
ABSTRACT On‐chip stimulated Brillouin scattering (SBS) technology has garnered attention in the field of integrated photonics due to its unique acousto–optic coupling characteristics and potential for all‐optical signal processing systems. By leveraging efficient Brillouin acousto–optic interactions, a variety of high‐performance on‐chip SBS‐based devices have been successfully demonstrated, including narrow‐linewidth lasers, low‐noise amplifiers, high‐precision gyroscopes, tunable filters, and optical isolators. In this review, we first summarize the physical mechanisms of SBS and the key methods for calculating gain characteristics on integrated optical platforms. We then discuss the implementation schemes of the Brillouin effect in different material platforms, along with their emerging applications in optical communications, quantum information, and other fields. Finally, we outline the current technological challenges and prospective research, which may provide insights into the design of next‐generation integrated acousto–optic devices.
ABSTRACT Liquid crystals (LCs), versatile soft materials endowed with intrinsic optical anisotropy and exceptional responsiveness to external stimuli, have emerged as a pivotal platform for advanced light‐field manipulation and integrated photonics. This review summarizes recent advances in microstructured LC devices, covering their fundamental properties, key degrees of freedom, and primary strategies for tunable optical field control. It focuses on three core research directions: linear optical control in LC‐based waveguides, nonlinear manipulation via spatial optical solitons, and lasing in LC microdroplets. A central theme is the unique ability of LC systems to transcend the geometric and functional constraints of conventional solid‐state photonics through dynamic, reconfigurable architectures. Looking forward, the field is poised for breakthroughs in multi‐field coupling mechanisms, the development of low‐loss, fast‐response LC materials, and practical applications in optical computing, adaptive optics, and beyond, thereby forging a vital bridge between fundamental optics and next‐generation integrated photonic technologies.
Fe‐based superconductors have attracted much attention. Among them, FeTe is unique in the series of FeSe 1‐ x Te x with absence of superconductivity. Interestingly, Fe 1+ y Te thin film shows superconductivity after oxygen annealing, and the mechanism is still elusive. This study investigates structural, superconducting, and magnetic properties of a series of Fe 1+ y Te thin films (FeTe:O x ) annealed under different oxygen partial pressures. Scanning transmission electron microscopy is used to examine the amount and distribution of excess Fe, the migration of excess Fe toward the film surface, and the structure and distribution of the iron oxide layer formed on the film surface. Exchange bias emerges at the interface between the ferromagnetic iron oxide and FeTe:O x , persisting in the superconducting state. Theoretical calculations suggest the occurrence of both interstitial oxygen and substitutional oxygen, and suppression of AFM order by the former, which can account for superconductivity. This work is helpful for understanding the interaction of oxygen with Fe 1+ y Te and mechanism of superconductivity for FeTe:O x thin films.
Cadmium stannate (Cd 2 SnO 4 ) exhibits both transparency and electrical conductivity, making it useful for applications where visible light needs to pass through the material while maintaining an electrical connection, such as in the manufacture of thin–film transistors for application in liquid crystal displays and other electronic devices. Most of the properties of Cd 2 SnO 4 have been investigated and are well documented. However, its thermoelectric properties have not been explored. The present study investigates its thermometric properties for the first time using density functional theory within the generalized gradient approximation, both without (GGA) and with the Hubbard correction (GGA+U). Quantum Espresso and BoltzTrap2 codes are utilized. The Perdew–Burke–Ernzerhof functional for solids exchange‐correlation functionals with ultrasoft pseudopotentials are involved in the calculations. The outcome showed that Cd 2 SnO 4 possesses desirable thermoelectric properties, of which some are better than those of the common thermoelectric materials. The Seebeck coefficient exhibited both positive and negative values, whereas the Hall coefficient verified its n‐type conductivity. The use of GGA+U resulted in higher values of the thermoelectric properties. Cd 2 SnO 4 can therefore be tried in the thermoelectric applications such as in magnetic sensors and magnetic memory storage due to its good thermoelectric properties. However, an experimental validation of the calculated thermoelectric properties is still required.
