Materials Science · Cross-listed from cs.IR
Beyond Text and Tables: Vision-Language Model Integration in ComProScanner for Extracting Materials Data from Scientific Figures with High Accuracy
Aritra Roy, Enrico Grisan, Chiara Gattinoni et al. (+1 more)
Automated extraction of materials composition-property data from scientific literature has advanced considerably with the development of large
language model-based pipelines; however, existing frameworks remain limited to textual and tabular content, overlooking the substantial proportion of quantitative property data reported exclusively in scientific figures. Here, we extend ComProScanner, a fully end-to-end multi-
agent framework for automated composition-property database construction, with a native
vision-
language model (VLM) based figure extraction capability. The extension introduces a FigureExtractor utility for caption-keyword-based figure filtering across all supported publishers, and a GraphExtractorTool
agent that passes extracted figures to a configurable VLM to recover composition-property pairs from scientific charts and plots. Four VLMs are selected for evaluation on the basis of the LMArena Diagram leaderboard with an input cost criterion of less than \$1.50 per million tokens. Benchmarking on 50 piezoelectric ceramic articles from the established $d_{33}$ test corpus demonstrates that Gemini-3-Flash-Preview achieves the highest performance with a composition accuracy of 0.97 and a normalised F1 score of 0.97, whilst remaining the most cost-effective model among the four evaluated. We additionally introduce a range-based value error threshold parameter into the evaluation framework, providing a more physically meaningful assessment of numeric property values extracted from figures than exact value matching. These contributions establish VLM-integrated ComProScanner as the first materials-specific, fully automated,
multimodal literature mining platform capable of extracting structured composition-property data from text, tables, and figures within a single unified pipeline.
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All authors Aritra Roy, Enrico Grisan, Chiara Gattinoni, John Buckeridge
Materials Science · Cross-listed from physics.app-ph
19 GHz Single-Ended-to-Balanced Modified Ladder-Lattice Filters Realized Using Periodically Polarized AlScN BAW Resonators
Merrilyn M. A. Fiagbenu, Shun Yao, Siddhant Sahoo et al. (+6 more)
We present a single-ended to balanced modified ladder-
lattice filter
topology, realized with periodically polarized piezoelectric (P3F) AlScN resonators, for single-ended to differential filtering applications. This filter
topology eliminates the need for baluns or other passive components and can interface, for instance, directly between differential
antennas and single-ended power and low noise amplifiers. Two filter designs operating at 19 GHz were implemented. The first design exhibited a minimum insertion loss of 1.3 dB, a 6.26% fractional 3-dB bandwidth, an average out-of-band rejection of 30 dB and occupied a 348 um x 476 um footprint, while the second higher-selectivity filter achieved 1.58 dB of minimum insertion loss, 5.11% fractional 3-dB bandwidth, 33 dB of average out-of-band rejection, and occupied a 392 um x 476 um footprint - Making them highly competitive for wireless communications filters. The working principle of the modified ladder-
lattice topology is discussed, the design of the filters are presented, and the linearity of the filters is explored through intermodulation and power handling measurements.
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All authors Merrilyn M. A. Fiagbenu, Shun Yao, Siddhant Sahoo, Mojtaba Hodjat-Shamami, Daeho Kim, Craig Moe, Pinal Patel, Ramakrishna Vetury, Roy H. Olsson III
Materials Science · Cross-listed from cond-mat.mes-hall
Coexisting Ballistic and Diffusive Heat Transport in Micrometer-Long Molecular Junctions
P. M. Martinez, O. Mateos-Lopez, J. C. Cuevas et al. (+1 more)
Boltzmann transport theory, the standard framework for predicting thermal conductivity, assumes that every vibrational mode eventually scatters, acquiring a finite lifetime that yields a convergent, length-independent thermal conductivity:
Fourier's law. Here we show that this assumption fails in a real molecular system. Through atomistic simulations of Au-alkane-Au single-molecule junctions spanning five orders of magnitude in length (0.5 nm to 4 $\mu$m), we find that thermal conductivity never converges. Transport is ballistic for up to one hundred nanometers at room temperature, extending nearly two orders of magnitude beyond existing single-molecule measurements. Past this window, conductivity diverges as $L^{1/3}$, the scaling predicted by the Kardar-Parisi-Zhang universality class for momentum-conserving systems. Frequency-resolved decomposition of the heat current reveals the mechanism behind the divergence. Low-frequency acoustic modes never thermalize: protected by momentum conservation, they remain ballistic at every chain length, still carrying 50% of the total heat current at $L = 2 \mu$m. All other modes thermalize collectively as discrete vibrational states merge into scattering-active
phonon bands with increasing length. Hence, the diverging conductivity emerges from the boundary between these coexisting transport regimes: as $L$ grows, the onset of scattering shifts progressively toward lower frequencies, suppressing the ballistic channel at a rate that sustains the $L^{1/3}$ divergence, leaving a finite contribution at every length. This coexistence of permanent ballistic and well-behaved diffusive transport, anticipated in abstract one-dimensional
lattice models, survives the structural and chemical complexity of real micrometer-sized junctions.
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All authors P. M. Martinez, O. Mateos-Lopez, J. C. Cuevas, J. G. Vilhena
Materials Science · Cross-listed from physics.optics
Ultrafast excitation of Bloch plasmon polaritons in hyperbolic metamaterials with an extreme ultra-violet transient grating
Tlek Tapani, Hannes Kempf, Matteo Pancaldi et al. (+14 more)
Manipulating materials properties with light drives advances in materials science and photonics.
Hyperbolic metamaterials are promising candidates as next-generation
quantum optical media. They support Bloch plasmon polaritons, which are characterized by potentially infinite wave-vectors and long lifetimes, but cannot be excited through direct light illumination due to momentum mismatch. Here, we experimentally show that a transient grating, formed via interference of fully coherent seeded free-electron
laser pulses in a thin
insulator film, enables the excitation of Bloch plasmon polaritons in an underlying
hyperbolic metamaterial. Finite element simulations confirm the role of the transient grating in facilitating phase-matching and mode excitation. Our findings demonstrate a route to spatiotemporally excite Bloch plasmon polaritons modes, offering an alternative to permanently nanostructured gratings and potentially enabling ultrafast control of optical modes excitation.
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All authors Tlek Tapani, Hannes Kempf, Matteo Pancaldi, Laura Foglia, Emanuele Pedersoli, Roberta Totani, Adriana Valerio, Riccardo Mincigrucci, Ivaylo Nikolov, Miltcho B. Danailov, Aitor De Andrés, Roman Krahne, Paolo Vavassori, Filippo Bencivenga, Flavio Capotondi, Denis Garoli, Nicolò Maccaferri
Materials Science · Cross-listed from physics.app-ph
Ultrafast temperature diagnosis of dynamically compressed matter using millielectronvolt inelastic x-ray scattering beyond the first Brillouin zone
P. G. Heighway and J. S. Wark
We present calculations of the millielectronvolt-scale x-ray scattering spectra of multilayered dynamic-compression targets comprising an unstructured ablator layer and a crystalline, textured sample layer. Our model builds on the classic formulation of x-ray thermal diffuse scattering by Warren [B. E. Warren, Acta Crystallogr. 6, 803 (1953)] and includes both elastic and first-order (single-
phonon) inelastic scattering contributions to the dynamic structure factor $S(\mathbf{q},\omega)$. We focus on the umklapp scattering regime (i.e., at momentum transfers outside the first Brillouin zone) where the ablator scattering that threatens to overwhelm the inelastic scattering from the crystalline layer of interest is suppressed. We show that, despite the considerably more complex structure of the inelastic scattering spectra in this intermediate-$q$ regime, it is still possible to reliably deduce the temperature of the
crystal using Dornheim's Laplace-transform–based formalism [Dornheim et al., Phys.
Plasmas 30, 042707 (2023)], regardless of the details of the sample's texture.
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Materials Science
Sub-10 mK "In-cell" Magnetic Refrigeration for Cryogen-free Cryostats
Alexander M. Donald, Nicolas Silva, Christopher J. Ollmann et al. (+7 more)
A design and implementation of "in-
cell"
magnetic refrigeration to achieve sub-10 mK temperatures T in cryogen-free dilution refrigerators is presented. The ultra low temperatures below 5 mK are attained in finite
magnetic fields B up to 1 T. The holding time below 5 mK varies between about 3 to 30 hours, depending on the final
magnetic field after demagnetization process. The developed technique can be used to study low dimensional devices at ultra low electron temperatures in the High B/T regime.
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All authors Alexander M. Donald, Nicolas Silva, Christopher J. Ollmann, Roch Schanen, Chao Huan, Sangyun Lee, Dominique Laroche, Richard P. Haley, Mark W. Meisel, Rasul Gazizulin
Materials Science
Evaluating Blended Refrigerants for Thermochemical Energy Storage and Circular Refrigerant Recovery using Activated Carbons
H. Lucassen, A. Luna-Triguero and J. M. Vicent-Luna
The
climate crisis demands a rapid shift to sustainable energy technologies and higher efficiency in existing energy systems. Adsorption-based thermochemical energy storage is a promising alternative due to its high energy density and compatibility with renewable heat sources. In this work, we investigate the adsorption behavior of pure refrigerants (R32, R125, R134a, and R600) and their commercial blends (R410A, R407F, R417A, and R417C) in six activated carbons for thermochemical energy storage and circular refrigerant recovery. A multiscale computational workflow combining Monte Carlo simulations, thermodynamic modeling, and breakthrough simulations is developed to predict adsorption, storage, and separation behavior from pure-component adsorption data. The methodology integrates adsorption potential theory (APT), ideal adsorbed solution theory (IAST), and models for the isosteric heat of adsorption. In addition, an in-house computational framework is developed to calculate heats of adsorption and energy storage densities for both pure refrigerants and multicomponent mixtures. Although developed using molecular simulations as a
benchmark, the methodology is directly applicable to experimental studies, since it only requires adsorption isotherms of the pure components as input to evaluate the performance of refrigerant blends. The results show that refrigerant blends can achieve higher storage densities than their pure counterparts due to cooperative adsorption and more efficient molecular packing. Furthermore, the activated carbons selectively separate key refrigerant components, highlighting their potential for sustainable refrigerant recovery. Overall, this work provides a general framework for the rational design and screening of next-generation refrigerant blends for adsorption-driven energy storage and separation applications.
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Materials Science · Cross-listed from cond-mat.supr-con
Superconducting PdTe Thin Film Via Topotactic Transformation, Toward Topological Superconductors
Hee Taek Yi, Min Ge, Renjie Xie et al. (+5 more)
Topological
superconductors (TSCs) hosting Majorana zero modes (MZMs) offer a pathway to fault-tolerant
quantum computation. PdTe is a promising TSC candidate due to its topological surface states and a reasonable superconducting critical temperature of ~4.5 K. However, it has been challenging to grow PdTe thin films with bulk-like superconducting properties. Here, we show that high-quality, superconducting PdTe thin films can be grown using molecular beam epitaxy (MBE). The films exhibit a sharp superconducting transition (T_onset = 4.43 K with transition width of 0.06 K), comparable to that of bulk
crystals. This was made possible via a topotactic transformation from a PdTe_2 buffer layer to a PdTe phase by growing Pd on top under Te-deficient conditions. Structural and transport analyses confirm the NiAs-type structure of PdTe, as well as its two-dimensional superconducting behavior and excellent air stability. These findings suggest that the MBE-grown PdTe films and their
heterostructures are a promising platform for topological superconductivity and Majorana physics.
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All authors Hee Taek Yi, Min Ge, Renjie Xie, Colby J. Stoddard, David H. Yi, Xiaoyu Yuan, Xiong Yao, Seongshik Oh
Materials Science · Cross-listed from cond-mat.mes-hall
Excitation-Energy-Selective Control of Hot-Carrier Cooling via a Resonant Optical-Phonon Bottleneck in Graphene
Sachin Sharm, Elliott Walker, Rachael Myers-Ward et al. (+4 more)
Understanding and controlling hot-carrier relaxation in
graphene is crucial for advancing ultrafast optoelectronic and terahertz technologies. Here, we investigate carrier cooling dynamics in monolayer and
bilayer graphene using mid-infrared pump pulses (0.22-0.73 eV) and terahertz probe pulses. We uncover a pronounced, reproducible, and non-monotonic dependence of the carrier relaxation time on excitation
photon energy. Remarkably, within a narrow spectral window (0.42 to 0.48 eV), the carrier lifetime increases by an order of magnitude compared to a few picosecond-scale cooling observed at other energies. We show that this anomalous slowdown originates from a resonant enhancement of the optical-
phonon lifetime, causing accumulation and reabsorption of hot optical
phonons that suppress energy transfer to the
lattice. All observed behaviors are captured within a unified carrier-
phonon energy-balance framework, where excitation-energy-dependent variations of the effective optical-
phonon decay pathway govern the cooling dynamics. These findings demonstrate excitation-energy-selective control of hot-carrier relaxation in
graphene and provide new insight into non-
equilibrium carrier-
phonon interactions near the optical-
phonon bottleneck.
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All authors Sachin Sharm, Elliott Walker, Rachael Myers-Ward, Jenifer Hajzus, Yijing Liu, Paola Barbara, Ioannis Chatzakis
Materials Science · Cross-listed from cond-mat.mes-hall
Fröhlich-type Polarons in Isotopically Enriched Hexagonal Boron Nitride
Ioannis Chatzakis, Timur Abdilov, Elliot Walker et al. (+3 more)
Exciton-
phonon interactions play a central role in defining the optical response of hexagonal boron nitride (hBN), yet their quantitative determination has remained incomplete. Here, we reveal the Fröhlich-type
exciton-
phonon coupling in boron-10-enriched hBN using low-temperature cathodoluminescence. We resolve the indirect
exciton 5.95$\pm$0.02 eV together with its longitudinal optical (LO)
phonon replica detuned by 184$\pm$56 meV, enabling the extraction of a Fröhlich coupling constant $\alpha$=0.159 and a larger
exciton binding energy of 161 meV, larger than previously reported values for natural-abundance hBN, which is attributed to isotope enrichment. The inferred polaron radius exceeds the
lattice constant, indicating large-polaron behavior. We deduced an
exciton scattering time ~of 97 fs, corresponding to a homogeneous linewidth of ~6.76 meV. We further obtain a polaron binding energy of ~48 meV and an effective mass of 1.045 $m_0$. These results provide a direct quantitative characterization of
exciton-
phonon coupling in isotopically engineered hBN and establish a foundation for tailoring its
phonon-polaritonic and
quantum-optical properties.
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All authors Ioannis Chatzakis, Timur Abdilov, Elliot Walker, Jaime Freitas, Song Liu, James H. Edgar
Materials Science
Dataset-aware entropy-maximized active learning for machine-learned interatomic potentials
Meiyan Wang, Rishi Rao and Li Zhu
We present an active learning framework for efficiently generating training data for machine-learned interatomic potentials (MLIPs). The method combines local
entropy-driven molecular dynamics with global
dataset-aware filtering: a per-configuration
entropy term biases MD trajectories toward structurally diverse snapshots, while a global
entropy measure, the log-determinant of the fingerprint covariance
matrix of the entire
dataset, selects only those configurations that provide genuinely new information. We employ dual covariance modes (per-atom for disordered structures and per-config for ordered phases) to achieve broad coverage of configuration space. Combined with a pre-trained foundation model (Allegro-OAM-L) and analytical fingerprint gradients from Gaussian overlap
matrix eigenvalues, the framework produces high-quality domain-specific potentials with near- or sub-meV/atom accuracy on test data drawn from the same distribution at training-set sizes of order $10^{2}$ to $10^{3}$
entropy-selected DFT-labeled structures. We demonstrate the method on three systems spanning diverse bonding types and pressure-driven phase transitions: carbon (covalent), silicon (covalent/metallic), and NaCl (ionic). In learning curve comparisons against random molecular dynamics sampling at matched training set sizes ($N = 100$ to $800$), evaluated over three independent training-set draws per condition,
entropy-driven sampling achieves a factor of approximately $3$ to $10$ lower energy MAE at $N = 800$ on in-distribution holdouts across the three systems, with the magnitude of the gain depending on the bonding type and the size at which the random-MD baseline saturates.
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Materials Science · Cross-listed from physics.optics
2D GaSe-Based Single-Pixel Spectrometer via Electro-Optical Barrier Co-Modulation
Shibesh Pramanik, Rishabh Sahoo, Arnab Mondal et al. (+4 more)
Driven by the growing demand for miniaturized spectrometers for in-situ analysis, and point-of-care diagnostics, conventional spectrometers are often constrained by bulky architectures and pathlength-limited spectral resolution. Achieving high-resolution, single-pixel computational spectrometers is therefore critical for the realization of compact, on-chip systems. Here, we report a single-pixel spectrometer enabled by a single 2D material; few-layer GaSe-based photodetector, in which the Schottky barrier height modulation, governed jointly by applied bias and optical excitation, provides an efficient mechanism for spectral encoding without the need for bulky dispersive elements. The device exhibits a high peak-wavelength accuracy of ~0.78 nm across a broad operational bandwidth (300-700 nm) within a compact footprint of ~100 um^2 and resolves closely spaced spectral features with separations down to ~5 nm. The device operates at low bias (+/- 4V) with an ultralow dark current density ~0.3 pA/um^2 at 4V bias. These results establish a simple, scalable route toward compact, cost-effective spectroscopic systems for on-chip spectral sensing and portable hyperspectral imaging applications.
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All authors Shibesh Pramanik, Rishabh Sahoo, Arnab Mondal, Tithi Saha, Ankush Bag, Vibhav Bharadwaj Shivakumar, Rishi Maiti
Materials Science
Modeling phase separation in polymer-derived silicon carbonitride ceramics through extended machine learning molecular dynamics
Fabien Mortier, Sylvian Cadars, Olivier Masson et al. (+5 more)
Polymer-derived ceramics combine the thermal stability of ceramics with the versatile properties of carbon domains, but modeling their atomic-scale
evolution during processing remains elusive due to the limitations of traditional computational methods. To address this issue, here we develop and apply a machine learning interatomic potential for silicon carbonitride-based (Si-C-N-H) systems, trained on a diversified database of over 9000 configurations – including amorphous models, high-temperature states, surfaces, and
crystal structure predictions – to capture the full complexity of these materials. This potential enables large-scale molecular dynamics simulations of 8000-atom systems revealing the atomic-scale
evolution of the
polymer-derived ceramic during thermal treatment. A key result of this work is the occurrence of a phase separation where carbon domains progressively nucleate from the amorphous SiCN
matrix during thermal processing, forming distinct
graphene-like sheets while preserving the integrity of the ceramic network. The resulting models reproduce the experimental atomic pair distribution functions with exceptional fidelity, validating our approach and providing microscopic explanations for the material unique combination of ceramic and graphitic properties. In this process, defective 5- and/or 7-member carbon rings, mediate the transformation to stable 6-member aromatic structures. These findings offer new atomic-scale insights into the thermal stability and structural transformation pathways of
polymer-derived ceramics, while our methodology opens avenues for studying complex amorphous systems with first-principles accuracy at experimentally relevant scales.
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All authors Fabien Mortier, Sylvian Cadars, Olivier Masson, Mauro Boero, Guido Ori, Yun Wang, Samuel Bernard, Assil Bouzid
Materials Science · Cross-listed from cs.CV
Interpretable Computer Vision for Defect Detection in X-ray Tomography of Aerospace SiC/SiC Composites
Antonio Peña Corredor, Julien Lesseur, Romain Nunez et al. (+2 more)
Non-destructive testing of aerospace SiC/SiC composites via X-ray computed
tomography (XCT) relies on expert visual assessment, with current workflows offering limited traceability for accept/reject decisions. Deep convolutional networks can automate defect detection, yet their black-box nature conflicts with the transparency that industrial inspection practice demands. To close this gap, we introduce p-ResNet-50, a convolutional framework extended with a prototype layer that couples high detection accuracy with case-based explanations. Six learned prototypes are explicitly aligned with expert-defined semantic categories-healthy
matrix,
matrix–air interfaces, pores, line-like defects, and mixed morphologies-so that every classification is traceable to a physically meaningful reference. Two novel regularisation terms, anchor-based and medoid-based, tether prototypes to expert-selected patches and prevent prototype collapse, addressing a known limitation of prototype networks. Latent-space analysis via UMAP delineates semantically coherent sub-domains and maps zones of uncertainty where misclassifications concentrate, giving inspectors an explicit picture of where the model is-and is not-reliable. The framework is validated on an XCT patch
dataset of approximately 12,000 patches extracted from four defect-rich SiC/SiC laboratory specimens. Taking a black-box ResNet-50 as a baseline (ROC-AUC = 0.991), the prototype extension achieves comparable performance (accuracy 0.957 vs. 0.959; ROC-AUC 0.994 vs. 0.993) while trading a slight reduction in sensitivity for higher precision and specificity. Each decision is backed by representative evidence patches, and the model explicitly flags its uncertainty regions. Beyond defect mapping, the framework establishes a reusable methodology for
embedding domain-expert knowledge into prototype networks, applicable to other XCT inspection scenarios requiring traceable, auditable decisions.
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All authors Antonio Peña Corredor, Julien Lesseur, Romain Nunez, Paul Rivalland, Thomas Philippe
Materials Science · Cross-listed from cond-mat.str-el
Itinerant Nature of Spin-Density-Wave Order in Ruddlesden-Popper Nickelates
Jiong Mei, Tianyang Xie and Kun Jiang
The nature of magnetism in layered Ruddlesden-Popper nickelates remains a central open question, particularly in light of recent observations of
spin-wave-like
magnetic excitations in metallic multilayer compounds. Here, we develop a unified itinerant description of
spin-density-wave (SDW) order and
magnetic excitations in La$_3$Ni$_2$O$_7$ and La$_4$Ni$_3$O$_{10}$. The essential ingredient is the multilayer mirror structure of the NiO$_2$ blocks, which organizes the low-energy electronic states into mirror-even and mirror-odd sectors. We show that dominant interband nesting between mirror-opposite bands drives a mirror-selective itinerant SDW instability, whose collective modes naturally reproduce the experimentally observed
spin-wave-like spectra. In La$_4$Ni$_3$O$_{10}$, the SDW further induces a secondary mirror-even charge density wave, yielding intertwined
spin and charge textures. Our results demonstrate that magnetism in multilayer nickelates is fundamentally itinerant rather than local-moment in origin, and establish mirror-selective interband SDW order as a unifying organizing principle for
magnetic correlations in these systems.
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Materials Science
Lattice thermal conductivity decomposition: Peierls vs. non-Peierls contributions
Andrey Pereverzev
The Green-Kubo
lattice thermal conductivity computed using the full classical heat current of a crystalline solid is compared with results obtained from the quadratic component of the heat current and from the commonly used Peierls heat current. In addition, thermal conductivity within the relaxation time approximation is evaluated. Three crystalline systems are investigated: solid argon, a model of solid argon with alternating masses, and $\alpha$-quartz. For all materials considered, the thermal conductivities calculated using the quadratic and Peierls heat currents differ only slightly. In the case of $\alpha$-quartz, the optical
phonon contribution to the thermal conductivity is found to exceed that of the acoustic modes. The relaxation time approximation systematically underestimates the thermal conductivity in all three systems.
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Materials Science
Spin polarization enhancement in a single-layer Bi(1-x)Sb(x) alloy on Ag(111) via isovalent substitution
Javier D. Fuhr, Polina M. Sheverdyaeva, Paolo Moras et al. (+2 more)
Co-adsorption of Bi and Sb on Ag(111) at room temperature yields a single-layer Bi(1-x)Sb(x)
alloy with a rectangular 3xsqrt(3) structure containing four atoms per unit
cell (2/3 ML total coverage) and lacking long-range chemical order. We present an electronic structure study of this system combining angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations. To investigate the effect of inversion
symmetry breaking induced by substituting a heavier atom (Bi) with a lighter isoelectronic one (Sb) within a fixed crystallographic framework, we focused on a Bi-rich composition. ARPES measurements reveal four surface-state bands, in good agreement with DFT calculations based on a rectangular four-atom overlayer unit
cell. DFT calculations further show that Sb incorporation induces both in-plane and out-of-plane asymmetries in the electronic potential, leading to sizable
spin splitting and
spin polarization of the overlayer bands. Although these effects are partially reduced by interaction with the substrate, they remain significant. Our work illustrates, through a concrete model system, a general principle: incorporating a lighter isovalent element can significantly enhance
spin polarization, potentially offering a useful design guideline for understanding and engineering Rashba-related systems.
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All authors Javier D. Fuhr, Polina M. Sheverdyaeva, Paolo Moras, J. Esteban Gayone, Hugo Ascolani
Materials Science
Coherent terahertz magnon-phonon three-wave mixing in a layered antiferromagnet
Liangyue Li, Na Wu, Zhengwang Lin et al. (+9 more)
The coherent nonlinear dynamics between collective excitations, such as
magnons and
phonons, drive emergent phenomena in
quantum materials, yet their direct observation remains a central challenge. Here, using double-terahertz-pump optical-probe spectroscopy, we report the direct observation of coherent
magnon-
phonon three-wave mixing in the layered
antiferromagnetic insulator FePS$_{3}$. We resolve both second- and third-order nonlinear responses of
antiferromagnetic magnons and identify a suite of nonlinear couplings in two-dimensional (2D) coherent spectra, including definitive sum- and difference-frequency generation between
magnons and
phonons. These results lay the groundwork for exploiting coherent nonlinearities to entangle
magnetic and vibrational excitations, opening avenues for
quantum control and hybrid
quantum technologies in the terahertz regime.
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All authors Liangyue Li, Na Wu, Zhengwang Lin, Zefen Li, Lixin Liu, Emil Vinas Boström, Yuan Wan, Xinbo Wang, Jianlin Luo, Fucai Liu, Angel Rubio, Qi Zhang
Materials Science · Cross-listed from math-ph
Concurrent enforcement of polyconvexity and true-stress-true-strain monotonicity in incompressible isotropic hyperelasticity: application to neural network constitutive models
Maximilian P. Wollner, Dominik K. Klein, Herbert Baaser et al. (+2 more)
The design of physics-augmented neural networks (PANNs) for the purposes of constitutive modeling has received considerable
attention as of late for a variety of material behaviors. Here, we revisit the classical framework of isotropic incompressible hyperelasticity in light of recent advances in the study of constitutive inequalities. We show that polyconvexity implies true-stress-true-strain monotonicity for a large class of incompressible strain-energy functions. The resulting elastic law obeys the physically reasonable Legendre-Hadamard (or ellipticity) condition as well as the notion of increasing stress with increasing strain. These results then inform the architecture of four distinct PANNs which are subsequently calibrated to three different sets of experimental data each. We show that different PANN parametrizations - satisfying the same constitutive constraints a priori - have varying approximation power for the description of material behavior. Moreover, even when distinct parametrizations perform comparatively well within the calibration regime, they show pronounced differences in extrapolation. This observation motivates a critical discussion about the predictive power of PANNs which also has implications for the modeling of more complex material behavior by virtue of neural networks.
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All authors Maximilian P. Wollner, Dominik K. Klein, Herbert Baaser, Gerhard A. Holzapfel, Patrizio Neff
Materials Science
Spin Response Properties in Electronically Robust Ferromagnetic Strained CrSiSe$_3$ Monolayer under External Electric Fields
S. Solihin, Ahmad R. T. Nugraha and Muhammad Aziz Majidi
Integrating two-dimensional van der Waals magnets into field-effect spintronic devices requires robust charge stability and tunable
spin responses. In this study, we investigate the electronic, topological, magnonic, and magneto-optical properties of the strain-engineered
ferromagnetic CrSiSe$_3$ monolayer under out-of-plane external electric fields by using first-principles calculations. We find that for this material, the intrinsic charge sector, including the indirect band gap, charge Berry
curvature, optical conductivities, and magneto-optical Kerr effect spectra, exhibits exceptional robustness against applied fields up to 0.3 V/$\r{A}$. Conversely, the
spin degrees of freedom demonstrate highly sensitive tunability. Electrostatic gating significantly modulates the
spin Berry-like
curvature, driving a non-monotonic enhancement in the
spin Hall conductivity. Furthermore, external fields effectively tune collective
magnon excitations by modifying microscopic Heisenberg exchange interactions. Such coexistence of robust charge immunity and flexible
spin manipulation establishes the strained CrSiSe$_3$ monolayer as a promising platform for stable spintronic devices.
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Materials Science
Geometry-Dependent Crack Interaction and Toughening in Graphene
Suyeong Jin, Jung-Wuk Hong and Alexandre F. Fonseca
The interaction between neighboring cracks has been shown to strongly influence the fracture behavior of
graphene. While previous studies focused primarily on crack spacing, the role of crack width remains poorly understood. Here, computational simulations are performed to investigate the coupled effects of crack width and inter-crack spacing $(W_\text{gap})$ on the tensile response of
graphene containing parallel cracks. The results show that increasing crack width amplifies the sensitivity of mechanical properties to crack spacing, leading to significant enhancement of peak stress, fracture strain, and toughness at sufficiently large $W_\text{gap}$. For narrow cracks, crack coalescence dominates and causes brittle failure. In contrast, wider cracks promote delayed ligament rupture, increased energy absorption and ductile-like fracture behavior. The normalized toughness and fracture strain exceed those of equivalent single-crack systems by more than twofold. A crack-geometry design map is proposed to identify regimes of crack coalescence, independent propagation, and enhanced toughness.
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Materials Science
Mesoscale Domain Evolution Mechanism during Alternating Current (AC) Poling of Relaxor Ferroelectrics
Yuan-Jie Sun, Bo Wang and Long-Qing Chen
Ferroelectric domain variants that are energetically equivalent are expected to remain preserved during polarization reversal under a
symmetry-preserving electric field. However, recent experiments on relaxor-ferroelectric
crystals have revealed irreversible elimination of inclined domain walls during AC poling, while the underlying mesoscale mechanism remains unclear. Here, we investigate the domain-wall motion during AC poling of rhombohedral Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$–PbTiO$_3$ single
crystals containing both 71$^\circ$ and 109$^\circ$ domain walls within a quasi-two-dimensional laminated geometry using phase-field simulations. The simulations reveal that the domain-wall behavior during polarization reversal depends on the spacing ratio between the 71$^\circ$ and 109$^\circ$ domain walls. Closely spaced 71$^\circ$ domain walls undergo irreversible elimination, whereas more widely separated walls are preserved, while the 109$^\circ$ domain walls remain intact. A threshold ratio for domain-wall elimination is identified and found to depend on the mechanical boundary conditions. By tracking the domain-wall trajectories during the switching process, we attribute this behavior to unsynchronized motion of neighboring 71$^\circ$ domain walls arising from long-range elastic interactions when the walls become strongly coupled. This collective motion breaks the
symmetry between energetically equivalent domain variants and leads to irreversible domain-wall elimination during polarization reversal. These findings provide mechanistic insight into collective domain-wall
evolution during polarization reversal and suggest that proximity-driven
symmetry breaking may provide a mesoscale mechanism for domain engineering in ferroelectric materials with high domain-wall densities.
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