jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yichun Pan | Liqing Zhu | Y Charlie Hu | Xin Kong | Tao Wang | Wei Xie | Weihang Zhou
Source: Communications Physics (article, 2026-01-26)
Field: Materials Science — Materials Chemistry

Ultrafast spatial hole burning of excitonic emission in monolayer WS2 The transport of excitons lies at the heart of excitonic devices. Probing, understanding, and manipulating excitonic transport represents a critical step prior to their technological applications. In this work, we report experimental studies on the ultrafast nonlinear transport of excitons in monolayer WS2. Under intense optical pumping, we observe an ultrafast spatial hole burning effect in the excitonic emission profile, followed by a re-brightening at even higher pumping density. Through time- and spatially-resolved photoluminescence spectroscopy, we reveal the underlying mechanism responsible for these nontrivial excitonic diffusion dynamics. Our results demonstrate that the combined effects of ultrafast exciton-exciton annihilation, efficient hole trapping by intrinsic sulfur vacancy defects, and laser-induced photo-oxidation govern the evolution of exciton transport under strong optical excitation. The observed dynamics are in excellent agreement with our diffusion model simulations, providing new insights into the nonlinear excitonic transport behaviors as well as their optical control mechanism in two-dimensional semiconductors. Probing, understanding, and manipulating nontrivial excitonic transport in atomically thin transition metal dichalcogenides (TMDCs) is a long-standing challenge. Here, the authors report the observation of ultrafast spatial hole burning of excitonic emission in monolayer WS2 and reveal the underlying mechanism, showcasing the peculiar excitonic transportation in monolayer TMDCs. Exciton ; Monolayer ; Ultrashort pulse ; Photoluminescence ; Trapping ; Diffusion ; Biexciton 2D Materials and Applications ; Strong Light-Matter Interactions ; Neural Networks and Reservoir Computing
Authors: Simon Pinault | Daphné Héran | Davinia Brouckaert | Fabien Chauchard | Ryad Bendoula
Source: Applied Optics (article, 2026-02-09)
Field: Chemistry — Analytical Chemistry

Optics-based method for enhancing spectroscopic calibration model development Spectrometric calibration is a challenge for every application because a large number and variability of reference samples are required to develop an accurate and robust model. This study investigates the potential of improving spectrometer calibration by using physically simulated spectra to enhance the calibration data set and perform out-of-range predictions. For this purpose, 56 liquid samples covering a wide range of absorption and scattering properties are measured with a double integrating sphere setup and visible spectrometers. A Kubelka-Munk optical model is used to simulate the samples reflectance and transmittance spectra. A simple method of calibration enhancement is introduced, and its benefits are evaluated with a partial least squares regression model, in comparison to a classical calibration approach. Two cases are studied, one with wide variability among reference samples and one with a limited range. The proposed method shows promising results, especially in the second, hardest case. A further study is done to evaluate the impact of simulated data quantity on the models' results. It was found that the performances reach a maximum when the ratio between measured and simulated spectra is 1:2. Calibration ; Integrating sphere ; Transmittance ; Spectrometer ; Partial least squares regression ; Absorption (acoustics) ; Range (aeronautics) ; Scattering ; Spectral line Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Spectroscopy and Laser Applications
Authors: David Lindblom
Source: KTH Publication Database DiVA (KTH Royal Institute of Technology) (article, 2026-01-01)
Field: Materials Science — Metals and Alloys

Neutron Imaging and Constitutive Modeling of Hydrogen Embrittlement in Steels This thesis concerns the phenomenon of coupled hydrogen diffusion and fracture in steels from both experimental and computational perspectives. Hydrogen embrittlement, where the ingress of hydrogen (H) reduces a steel’s load-carrying capacity, is a long-standing scientific challenge, first documented in the late 19th century. W.H. Johnson observed that exposing pure iron to an acidic solution led to premature fracture and that the metal regained its original strength and ductility after being removed from the solution for a period. Despite more than a century of research, the mechanistic understanding of hydrogen embrittlement remains limited, primarily because of the multiscale nature of hydrogen behavior and its complex interactions with metallic microstructures. Hydrogen diffuses through thecrystal lattice and interacts with grain boundaries, carbides, voids, cracks, and dislocations. Under external mechanical loading, hydrogen transport is further influenced by dilatational lattice distortions and by moving dislocations, adding additional complexity. As a result, Fick’s law often fails to describe hydrogen diffusion in these systems accurately, and experimental investigations on the submicrometer, micrometer, and engineering scales remain challenging. This thesis addresses these challenges by combining fracture mechanics experiments with neutron imaging to investigate crack propagation caused by hydrogen embrittlement. Additionally, it presents a detailed numerical framework for modeling hydrogen embrittlement at the continuum scale. The strong coupling between mechanical fields and solute concentration necessitates advanced numerical techniques to solve the governing partial differential equations reliably and efficiently Hydrogen embrittlement ; Hydrogen ; Embrittlement ; Grain boundary ; Fracture mechanics ; Ductility (Earth science) ; Multiscale modeling Hydrogen embrittlement and corrosion behaviors in metals ; Material Properties and Failure Mechanisms ; Nuclear Physics and Applications
Authors: M. S. Boldin | E. A. Isupova | E. A. Lantcev | T. S. Pozdova | M. D. Nazmutdinov | D. A. Permin | A. A. Murashov | A. N. Sysoev | A. V. Nokhrin | V. N. Chuvil'deev
Source: ArXiv.org (article, 2026-01-12)
Field: Materials Science — Ceramics and Composites

Effect of the parameters of bimodal microstructure on the mechanical properties of alumina: A case of sintering regime effects The effect of sintering regimes on the density, microstructure parameters, and mechanical properties of Al2O3 and Al2O3 + 0.25%MgO ceramics has been investigated. The ceramics were sintered in three regimes: Regime I - heating at a constant rate (2.5, 5, 10, 20 C/min) up to the temperature T=1650C; Regime II - heating with a varied heating rate up to 1565C with the duration corresponding to sintering at the heating rate of 10 C/min in Regime I followed by a three-fold decrease in the shrinkage rate; Regime III - two-stage sintering: heating according to Regime II up to the temperature T1+1550C, then lowering the temperature down to T2 = 1300-1500C and holding for 3 h at the T2. The sintering regimes were chosen so that the ceramics had the relative density of 97-99% and a bimodal distribution of the microstructure parameters. The Al2O3 and Al2O3 + 0.25%MgO ceramics obtained in Regimes I-III had a microstructure with abnormally large grains in a fine-grained matrix. The sizes and volume fractions of the large grains depended on the sintering regime. Most abnormally large grains had elongated shapes that leads to deviations in the crack propagation trajectories from the straight line. The optimal parameters of the bimodal microstructure parameters distribution providing enhanced mechanical properties of the ceramics (hardness, indentation fracture toughness, ultimate strength) have been determined. Microstructure ; Sintering ; Ceramic ; Shrinkage ; Indentation ; Volume (thermodynamics) Advanced ceramic materials synthesis ; Advanced materials and composites ; Microwave Dielectric Ceramics Synthesis
Authors: Hernán R. Sánchez
Source: Journal of Chromatography A (article, 2026-03-25)
Field: Chemistry — Spectroscopy

Chromatographic peak shape from a stochastic model: Analytic time-domain expression in terms of physical parameters and conditions under which heterogeneity reduces tailing Decoupling (probability) ; Expression (computer science) ; Gaussian ; Representation (politics) ; Residual ; Function (biology) ; Variance (accounting) ; Poisson distribution ; Standard deviation ; Benchmark (surveying) Analytical Chemistry and Chromatography ; Protein purification and stability ; Chromatography in Natural Products
Authors: Dattatray Gadkari
Source: International Journal on Science and Technology (article, 2026-01-22)
Field: Materials Science — Materials Chemistry

Experimental Investigation of Entirely Detached Growth in Vertical Directional Solidification and Crystallization Evolution Vertical Directional Solidification (VDS) process produces entirely detached, diffusion-controlled crystallization of Sb-based III–V alloys, binary - InSb, GaSb, doped derivatives, ternary In(1-X)GaXSb, and In0.5Ga0.5Sb alloys under fully terrestrial conditions. Establishing a vapor-rich, pressure-compensated melt environment and the axial gradients (10–32 °C·cm⁻¹), by naturally suppresses buoyancy-driven flow and shear stress at the ampoule boundary. This creates a quasi-equilibrium vapor–melt–crystal domain where solute transport becomes overwhelmingly governed by thermodiffusion and diffusion, yielding a stable, thick diffusion boundary layer. VDS experimental results reveal uniform compositions (Δx &lt; 0.01), insignificant segregation, and high structural perfection (FWHM 49–128 arcsec). Entire interface detachment attained across all compositions eliminates wall-induced perturbations and establishes the classical Concave → Planar → Convex meniscus alike crystallization obtained in space growth or in microgravity. Quantitative evaluation of thermal diffusion, diffusion fluxes, interface thermodynamics, and detachment parameters confirms repeats (~80 runs) of the transport physics of solidification. VDS results constitutes a dynamic terrestrial crystallization, enabling superior morphological stability, controlled solute redistribution, and exceptional crystalline quality. Crystallization ; Directional solidification ; Diffusion ; Crystal growth ; Thermal ; Meniscus ; Supercooling ; Shear (geology) ; Ternary operation ; Planar Solidification and crystal growth phenomena ; Phase-change materials and chalcogenides ; Intermetallics and Advanced Alloy Properties
Authors: A. D. Drozin | M. V. Dudorov
Source: Izvestiya Ferrous Metallurgy (article, 2026-01-08)
Field: Materials Science — Materials Chemistry

Criteria for the existence of local equilibria in supercooled melts The paper is intended for researchers studying of supercooled metallic melts. It addresses an important theoretical problem: the possibility of establishing local thermodynamic equilibrium at the phase boundary during crystallization from a supercooled melt. Such processes play a crucial role in determining the microstructure of materials during solidification, particularly under rapid cooling conditions characteristic of modern metallurgical and powder technologies. During supercooling, nuclei of a new, solid phase begin to form in the melt. To mathematically describe the growth of such nuclei, it is necessary to specify boundary conditions that define the composition of the adjacent liquid phase. Traditional models assume that local equilibrium can be established near the nucleus and that its parameters can be derived from the equilibrium phase diagram. However, as demonstrated by our study of binary systems, local equilibrium may, in some cases, be fundamentally unattainable. This article presents a theoretical analysis of the conditions under which equilibrium may or may not be established. The analysis considers chemical potentials of the components in both the solid nucleus and the liquid melt. Based on the equilibrium phase diagram of the corresponding macrosystem, one can infer the relative chemical potentials of the components in each phase. It is shown that when the nucleus consists of a single component, local equilibrium is always possible in principle. However, when the nucleus is a solution, equilibrium may only be realized under specific thermodynamic conditions. In such cases, the application of first-kind boundary conditions becomes invalid, and it is necessary to take into account the rates of chemical reactions involved in the interphase transfer of each component. Supercooling ; Phase diagram ; Thermodynamic equilibrium ; Boundary (topology) ; Crystallization ; Equilibrium thermodynamics ; Phase (matter) ; Boundary value problem ; Chemical equilibrium Solidification and crystal growth phenomena ; Metallurgical and Alloy Processes ; Material Science and Thermodynamics
Authors: Georgy Alymov | Dmitry Svintsov
Source: physica status solidi (a) (article, 2026-01-01)
Field: Materials Science — Materials Chemistry

Ultimate Sharpness of the Tunneling Resonance in Van der Waals Heterostructures Heterostructures comprised of a 2D emitter and collector separated by a dielectric exhibit resonant tunneling when the band structures of both 2D materials are aligned. It is commonly assumed that the height and width of the resonant peak in the tunneling current are determined by electron scattering and rotational misalignment of the 2D materials. In this article, two fundamental factors limiting the maximum height and steepness of the resonance are identified: coupling to the contacts and tunnel splitting of energy levels. The upper limit of the tunneling current is the number of electrons available for tunneling times half the tunnel coupling between the emitter and collector. As a result of a tradeoff between the contact‐induced level broadening and contact resistance, the maximum current is only achievable when the coupling to the contacts equals the tunnel level splitting. According to model calculations, the limiting behavior can be observed in double‐gated graphene/few‐layer hexagonal boron nitride/graphene heterostructures. Quantum tunnelling ; Common emitter ; Resonance (particle physics) ; Electron ; Tunnel effect ; Heterojunction ; Coupling (piping) ; Scattering Graphene research and applications ; 2D Materials and Applications ; Topological Materials and Phenomena
Authors: Jinjian Guo | Kang Zhao | Yishan An | Zhiyong Quan | Mankang Zhu | Xiaohong Xu | Xuedong Bai
Source: Communications Physics (article, 2026-03-24)
Field: Materials Science — Materials Chemistry

Collective dynamics of polar nanoregions enhance electrical properties via solid-solution-induced entropy increase in KBT relaxors Relaxor ferroelectrics (RFEs) are renowned for excellent electromechanical properties, primarily driven by the presence of polar nanoregions (PNRs). Recent advances, including the entropy-increase strategy via various designs, enhance PNR density and disorder, but the underlying collective dynamics of PNRs and their impact on RFE electrical properties have received less attention. Here, we investigate the role of PNR collective dynamics by using K0.5Bi0.5TiO3 (KBT) as a model system and progressively enhancing PNR density through doping with Bi(Ni0.5Zr0.5)O3. It significantly improves KBT’s electrostrain and energy storge. We observe 10-1000 nm PNR mesostructures self-assembled from 2-4 nm PNRs, and via the Gray-Scott model, confirm their origin from Turing instability in PNR groups (a universal nanoscale self-organization mechanism for RFEs). And the jamming effects within these mesostructures play a key role in enhancing electrical properties. Our findings shed light on RFE’s structure-property relationships and provide guiding principles for designing other high-performance RFEs. Relaxor ferroelectrics (RFEs) are widely used for their excellent electrical properties rooted in polar nano regions (PNRs), yet how PNRs’ collective dynamic behavior impacts material performance is poorly understood. Taking KBT RFEs as a model, the authors identify unique PNR mesostructures, reveal their Turing instability origin, and clarify jamming effects as key to boosting their electrical properties. Polar ; Instability ; Jamming ; Polarity (international relations) ; Entropy (arrow of time) ; Collective behavior ; Boosting (machine learning) Ferroelectric and Piezoelectric Materials ; Dielectric materials and actuators ; Advanced Sensor and Energy Harvesting Materials
Authors: Jiajun Zhao | Chao Yang | Liu Xi | Shaosong Huang | Dan Sun | Ping Chen | Jijun Zhao | Yuanyuan Wang
Source: Journal of Applied Physics (article, 2026-01-02)
Field: Materials Science — Materials Chemistry

Mechanisms of U and Si diffusion in Fe–X (X = Cr, Al) dilute alloys from first-principles Fuel–cladding chemical interaction (FCCI) is a key factor driving cladding degradation in the promising U3Si2–FeCrAl accident-tolerant fuel system, yet predictive insights into fuel element diffusion in cladding alloys remains limited. To elucidate the fundamental diffusion mechanisms, this work develops computational methodology that integrates the residence-time algorithm with the nine-frequency and oversized solute-atom models based on first-principles calculations. We apply this integrated approach to model the diffusion of U and Si in Fe–Cr and Fe–Al alloys, which serve as simplified model systems for the complex FeCrAl cladding. Our results reveal that U diffusion is markedly slower than Si due to the significant lattice strain and highly directional bonding of U. Moreover, alloying elements Cr and Al both suppress the diffusion of U and Si, with Cr exhibiting a stronger inhibitory effect than Al. This integrated strategy enables a rigorous description of atomic transport, providing the fundamental understanding of FCCI mechanisms and guiding the design of advanced accident-tolerant nuclear fuels. Cladding (metalworking) ; Diffusion ; Lattice (music) ; Work (physics) ; Atomic diffusion ; Lattice diffusion coefficient ; Finite element method Nuclear Materials and Properties ; Nuclear reactor physics and engineering ; Molten salt chemistry and electrochemical processes
Authors: Judith Grafenhorst | Sarah Krebber | Kristin Kliemt | Cornelius Krellner | Elena Hassinger | U. Stockert
Source: ArXiv.org (article, 2026-02-10)
Field: Materials Science — Materials Chemistry

Giant thermopower changes related to the resistivity maximum and colossal magnetoresistance in EuCd2P2 We present the thermopower of EuCd2P2, a material which exhibits a large resistivity peak with significant magnetic field dependence in the temperature range of 10-25 K. In the same region we observe a highly unusual behavior of the thermopower with two sign changes and giant extrema. The overall variation of the thermopower exceeds 4 000 muV/K and takes place in an extremely narrow temperature region of less than 5 K. The anomaly is suppressed completely in a small magnetic field of 0.5 T. We discuss this observation using a simple drift-diffusion picture and taking into account that the temperature gradient inducing the thermopower voltage is accompanied by a gradient of the electrical resistivity. Our simple estimation yields the correct magnitude, shape, and field dependence of the thermopower anomaly observed in EuCd2P2. These results open a new route to giant thermopower values via gradients of electronic properties. Seebeck coefficient ; Electrical resistivity and conductivity ; Giant magnetoresistance ; Magnetoresistance ; Colossal magnetoresistance ; Anomaly (physics) ; Magnetic field Advanced Thermoelectric Materials and Devices ; Rare-earth and actinide compounds ; Thermal Expansion and Ionic Conductivity
Authors: Md. Sultanur Rahman | Israt Zahan | Faisal Ahmed
Source: Scientia. Technology, science and society. (article, 2026-02-01)
Field: Materials Science — Materials Chemistry

A Comprehensive Review of Thermal Anisotropy in Inorganic Functional Materials: Characterization Techniques and Applications Thermal transport has become a critical design parameter in inorganic functional materials, especially as modern electronic, photonic, and energy devices operate at higher power densities and smaller dimensions. A key feature of many advanced inorganic systems is thermal anisotropy, meaning that heat conduction differs significantly depending on crystallographic direction. Such anisotropy arises from directional bonding, lattice symmetry, phonon dispersion, microstructural alignment, and interface-dominated transport. Thermal anisotropy can be beneficial because it enables directional heat spreading and selective thermal insulation, but it can also create thermal gradients and reliability issues if not properly understood. This review summarizes the theoretical foundations of anisotropic thermal transport, the primary inorganic material classes exhibiting thermal anisotropy, and the most widely used experimental characterization approaches. A major emphasis is placed on thermal measurement strategies, interpretation challenges, and common sources of uncertainty when quantifying in-plane and cross-plane thermal conductivity. Finally, the review discusses emerging applications, including thermal management in electronics, thermoelectric energy conversion, phase-change and neuromorphic devices, solid-state batteries, and extreme-environment systems. The paper concludes by highlighting current challenges, knowledge gaps, and future opportunities for engineering thermal anisotropy through defect control, strain, heterostructure design, and microstructural orientation control. Anisotropy ; Characterization (materials science) ; Phonon ; Thermal ; Thermal conduction ; Thermal conductivity ; Thermal resistance ; Thermoelectric effect Thermal properties of materials ; Advanced Thermoelectric Materials and Devices ; Thermal Expansion and Ionic Conductivity
Authors: Cooper Selco | Christian Bengs | Chaitali Shah | Ashok Ajoy
Source: arXiv (Cornell University) (article, 2026-04-03)
Field: Materials Science — Materials Chemistry

Breakdown of Disorder-Suppressed Floquet Heating under Two-Frequency Driving Periodic (Floquet) driving enables Hamiltonian engineering and nonequilibrium phases, but interacting systems eventually heat by absorbing energy from the drive. Disorder can greatly delay this process, yielding long-lived prethermal plateaus. Here we show that this protection can fail when pulse-train control introduces a second driving frequency and when the disorder fluctuates. Using a natural-abundance 13C nuclear-spin network in diamond, we observe sharp peaks in the late-time heating rate at the double- and triple-spin-flip resonance conditions predicted by bimodal Floquet interference, and track their evolution with drive frequency. A switching-noise model attributes the resonant absorption to stochastic electron-spin dynamics that intermittently tune rare nuclear clusters into multi-photon resonance. Our results reveal a resonance-activated limit for disorder-stabilized Floquet phases and suggest new routes to DC-field quantum sensing based on an abrupt breakdown of prethermalization. Floquet theory ; Non-equilibrium thermodynamics ; Hamiltonian (control theory) ; Quantum tunnelling ; Quantum ; Limit (mathematics) ; Resonance (particle physics) ; Energy (signal processing) Diamond and Carbon-based Materials Research ; Force Microscopy Techniques and Applications ; Mechanical and Optical Resonators