jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Michele Conroy | Didrik R. Småbråten | Colin Ophus | Konstantin Shapovalov | Quentin M. Ramasse | Kasper A. Hunnestad | Sverre M. Selbach | Ulrich Aschauer | Kalani Moore | J. M. Gregg | U. Bangert | Massimiliano Stengel | Alexei Gruverman | Dennis Meier
Source: White Rose Research Online (University of Leeds, The University of Sheffield, University of York) (preprint, 2023-09-05)
Field: Materials Science — Materials Chemistry

Observation of Antiferroelectric Domain Walls in a Uniaxial Hyperferroelectric Ferroelectric domain walls are a rich source of emergent electronic properties and unusual polar order. Recent studies showed that the configuration of ferroelectric walls can go well beyond the conventional Ising-type structure. Néel-, Bloch-, and vortex-like polar patterns have been observed, displaying strong similarities with the spin textures at magnetic domain walls. Here, we report the discovery of antiferroelectric domain walls in the uniaxial ferroelectric Pb$_{5}$Ge$_{3}$O$_{11}$. We resolve highly mobile domain walls with an alternating displacement of Pb atoms, resulting in a cyclic 180$^{\circ}$ flip of dipole direction within the wall. Density functional theory calculations reveal that Pb$_{5}$Ge$_{3}$O$_{11}$ is hyperferroelectric, allowing the system to overcome the depolarization fields that usually suppress antiparallel ordering of dipoles along the longitudinal direction. Interestingly, the antiferroelectric walls observed under the electron beam are energetically more costly than basic head-to-head or tail-to-tail walls. The results suggest a new type of excited domain-wall state, expanding previous studies on ferroelectric domain walls into the realm of antiferroic phenomena. Condensed matter physics ; Ferroelectricity ; Antiferroelectricity ; Dipole ; Domain wall (magnetism) ; Antiparallel (mathematics) ; Domain (mathematical analysis) ; Materials science ; Polar ; Physics ; Dielectric ; Magnetization ; Magnetic field Ferroelectric and Piezoelectric Materials ; Acoustic Wave Resonator Technologies ; Solid-state spectroscopy and crystallography
Authors: Arjun Raghavan | Marisa Romanelli | Julian May-Mann | Anuva Aishwarya | Leena Aggarwal | Anisha G. Singh | Maja D. Bachmann | Leslie M. Schoop | Eduardo Fradkin | I. R. Fisher | Vidya Madhavan
Source: arXiv (Cornell University) (preprint, 2023-08-30)
Field: Materials Science — Materials Chemistry

Atomic-Scale Visualization of a Cascade of Magnetic Orders in the Layered Antiferromagnet $GdTe_{3}$ $GdTe_{3}$ is a layered antiferromagnet which has attracted attention due to its exceptionally high mobility, distinctive unidirectional incommensurate charge density wave (CDW), superconductivity under pressure, and a cascade of magnetic transitions between 7 and 12 K, with as yet unknown order parameters. Here, we use spin-polarized scanning tunneling microscopy to directly image the charge and magnetic orders in $GdTe_{3}$. Below 7 K, we find a striped antiferromagnetic phase with twice the periodicity of the Gd lattice and perpendicular to the CDW. As we heat the sample, we discover a spin density wave with the same periodicity as the CDW between 7 and 12 K; the viability of this phase is supported by our Landau free energy model. Our work reveals the order parameters of the magnetic phases in $GdTe_{3}$ and shows how the interplay between charge and spin can generate a cascade of magnetic orders. Condensed matter physics ; Antiferromagnetism ; Charge density wave ; Charge ordering ; Superconductivity ; Cascade ; Physics ; Electron ; Charge (physics) ; Chemistry ; Quantum mechanics 2D Materials and Applications ; Iron-based superconductors research ; Magnetic and transport properties of perovskites and related materials
Authors: Kévin Renault | Yoan Capello | Shun Yao | Sami Halila | Anthony Romieu
Source: ChemRxiv (preprint, 2023-03-22)
Field: Materials Science — Materials Chemistry

Arylidene Meldrum's Acid: A Versatile Structural Motif for the Design of Enzyme-Responsive "Covalent-Assembly" Fluorescent Probes with Tailor-Made Properties Latent cyclic carbon-centered nucleophiles (latent C-nucleophiles) are recently proving their value in the field of reaction-based fluorescent probes, far beyond their primary utility in organic synthesis. They are typically used to introduce a Michael acceptor moiety acting as a recognition/reaction site for analyte to be detected or as a kinetic promoter of fluorogenic cascade reactions triggered by a reactive species. C-nucleophiles bearing a further reactive handle offer an additional opportunity for tuning the physicochemical/targeting properties or providing drug-releasing capabilities to these probes, through the covalent attachment of ad hoc chemical moiety. In order to implement such strategy to fluorogenic/chromogenic enzyme substrates based on the "covalent-assembly" principle, we have explored the potential of some functionalized derivatives of barbituric acid, piperidine-2,4-dione and Meldrum's acid. Our investigations based on the rational design and analytical validations of enzyme-responsive caged precursors of fluorescent pyronin dyes and 7-(diethylamino)coumarin-3-carboxylic acid, led to identify a versatile candidate suitable for this late-stage structural optimization approach with a minor impact on stability and activation kinetics of probe. This Meldrum's acid derivative, synthesized from levulinic acid, enables to either enhance water solubility or achieve the reversible conjugation of a targeting ligand, while promoting in situ formation of fluorophore upon enzymatic activation. This study opens the way to novel multifunctional fluorescence imaging probes and optically modulated small conjugate-based theranostics drawing on the promising "covalent-assembly" strategy. Moiety ; Nucleophile ; Chemistry ; Fluorophore ; Rational design ; Covalent bond ; Combinatorial chemistry ; Fluorescence ; Organic chemistry ; Nanotechnology ; Materials science ; Catalysis Luminescence and Fluorescent Materials ; Click Chemistry and Applications ; Supramolecular Self-Assembly in Materials
Authors: Fatim-Zahra Mouhib | Bo Gao | Talal Al‐Samman
Source: arXiv (Cornell University) (preprint, 2023-08-17)
Field: Materials Science — Biomaterials

On the role of selective nucleation and growth to recrystallization texture development in a Mg-Gd-Zn alloy One of the main material properties altered by rare earth additions in magnesium alloys is texture, which can be specifically adjusted to enhance ductility and formability. The current study aims at illuminating the texture selection process in a Mg-0.073at%Gd-0.165at%Zn alloy by investigating recrystallization nucleation and early nucleus growth during static recrystallization. An as-cast sample of the investigated alloy was deformed in uniaxial compression at 200°C till 40% strain and was then cut into two halves for subsequent microstructure characterization via ex-situ and quasi in-situ EBSD investigations. In order to gain insights into the evolution of texture during recrystallization, the contributions from dynamic and static recrystallization were initially separated and the origin of the non-basal orientation of recrystallization nuclei was traced back to several potential nucleation sites within the deformed matrix. Considering the significant role of double-twin band recrystallization in determining the recrystallization texture, this type of recrystallization nucleation was further investigated via quasi-in-situ EBSD on a deformed sample, annealed at 400° for different annealing times. With progressive annealing a noticeable trend was observed, in which the basal nuclei gradually diminished and eventually vanished from the annealed microstructure. In contrast, the off-basal nuclei exhibited continuous growth, ultimately becoming the dominant contributors to the recrystallization texture. The study therefore emphasizes the importance of particular nucleation sites that generate favorably oriented off-basal nuclei, which over the course of recrystallization outcompete the neighboring basal-oriented nuclei in terms of growth, and thereby dominate the recrystallization texture. Recrystallization (geology) ; Nucleation ; Materials science ; Electron backscatter diffraction ; Annealing (glass) ; Dynamic recrystallization ; Alloy ; Microstructure ; Metallurgy ; Crystallography ; Composite material ; Hot working ; Chemistry ; Geology Magnesium Alloys: Properties and Applications ; Hydrogen Storage and Materials ; Aluminum Alloys Composites Properties
Authors: Marı́a de la Mata | Alberto Sanz de León | Luisa M. Valencia-Liñán | Sergio I. Molina
Source: Research Square (preprint, 2023-09-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Plasmonic Characterization of 3D Printing Metal-Polymer Nanocomposites Abstract Plasmonic polymer nanocomposites (i.e., polymer matrices containing plasmonic nanostructures) are appealing candidates for the development of manifold technological devices relying on light-matter interactions, provided their inherent properties and processing capabilities. The smart development of plasmonic nanocomposites requires from in-depth optical analyses proving the material performance, along with correlative studies guiding the synthesis of tailored materials. Importantly, plasmon resonances emerging from metal nanoparticles affect the macroscopic optical response of the nanocomposite, leading to far- and near-field perturbations useful to address the optical activity of the material. We analyze the plasmonic behavior of two nanocomposites suitable for 3D printing, based on acrylic resin matrices loaded with Au or Ag nanoparticles. We compare experimental and computed UV-Vis macroscopic spectra (far-field) with single particle EELS analyses (near-field). We have extended the calculations of Au and Ag plasmon related resonances over different environments and nanoparticle sizes. Discrepancies between UV-Vis and EELS are dependent on the interplay between the metal considered, the surrounding media and the size of the nanoparticles. The study allows comparing in detail the plasmonic performance of Au- and Ag- polymer nanocomposites, whose plasmonic response is better addressed accounting for their intended applications (i.e., whether they rely on far- or near- field interactions). Plasmon ; Nanocomposite ; Materials science ; Nanoparticle ; Nanotechnology ; Characterization (materials science) ; Polymer ; Nanostructure ; Plasmonic nanoparticles ; Optoelectronics ; Composite material Gold and Silver Nanoparticles Synthesis and Applications ; Nonlinear Optical Materials Studies ; Photoacoustic and Ultrasonic Imaging
Authors: Mateo Uldemolins | Andrej Mesaroš | Genda Gu | Alexandra Palacio‐Morales | M. Aprili | Pascal Simon | Freek Massee
Source: arXiv (Cornell University) (preprint, 2023-10-09)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Interaction-driven quantum phase transition of a single magnetic impurity in Fe(Se,Te) Understanding the interplay between individual magnetic impurities and superconductivity is crucial for bottom-up construction of novel phases of matter. For decades, the description by Yu, Shiba and Rusinov (YSR) of single spins in a superconductor and its extension to include quantum effects has proven highly successful: the pair-breaking potential of the spin generates sub-gap electron- and hole excitations that are energetically equidistant from zero. By tuning the energy of the sub-gap states through zero, the impurity screening by the superconductor makes the ground state gain or lose an electron, signalling a parity breaking quantum phase transition. Here we show that in multi-orbital impurities, correlations between the in-gap states can conversely lead to a quantum phase transition where more than one electron simultaneously leave the impurity without significant effect of the screening by the superconductor, while the parity may remain unchanged. This finding implies that the YSR treatment is not always valid, and that intra-atomic interactions, particularly Hund's coupling that favours high spin configurations, are an essential ingredient for understanding the sub-gap states. The interaction-driven quantum phase transition should be taken into account for impurity-based band-structure engineering, and may provide a fruitful basis in the search for novel physics. Condensed matter physics ; Quantum phase transition ; Superconductivity ; Spins ; Physics ; Impurity ; Quantum phases ; Magnetic impurity ; Band gap ; Electron ; Quantum ; Spin (aerodynamics) ; Ground state ; Phase transition ; Quantum mechanics Iron-based superconductors research ; Physics of Superconductivity and Magnetism ; Rare-earth and actinide compounds
Authors: A. S. Moskvin
Source: arXiv (Cornell University) (preprint, 2023-06-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Jahn-Teller magnets A wide class of materials with different crystal and electronic structures from quasi-two-dimensional unconventional superconductors (cuprates, nickelates, ferropnictides/chalcogenides, ruthenate SrRuO$_4$), 3D systems as manganites RMnO$_3$, ferrates (CaSr)FeO$_3$, nickelates RNiO$_3$, to silver oxide AgO are based on Jahn-Teller $3d$ and $4d$ ions. These unusual materials called Jahn-Teller (JT) magnets are characterized by an extremely rich variety of phase states from non-magnetic and magnetic insulators to unusual metallic and superconducting states. The unconventional properties of the JT-magnets can be related to the instability of their highly symmetric Jahn-Teller "progenitors" with the ground orbital $E$-state to charge transfer with anti-Jahn-Teller $d$-$d$ disproportionation and the formation of a system of effective local composite spin-singlet or spin-triplet, electronic or hole $S$-type bosons moving in a non-magnetic or magnetic lattice. We consider specific features of the anti-JT-disproportionation reaction, properties of the electron-hole dimers, possible phase states of JT-magnets, effective Hamiltonians for single- and two-band JT-magnets, and present a short overview of physical properties for actual JT-magnets. Jahn–Teller effect ; Condensed matter physics ; Magnet ; Superconductivity ; Disproportionation ; Ground state ; Magnetic susceptibility ; Singlet state ; Physics ; Materials science ; Ion ; Chemistry ; Excited state ; Atomic physics ; Quantum mechanics Magnetic and transport properties of perovskites and related materials ; Rare-earth and actinide compounds ; Magnetic Properties of Alloys
Authors: Paulo Roberto de Oliveira | Roberto Rittner | Palimécio G. Guerrero | Patrick R. Batista | Gustavo Nunes de Oliveira Costa
Source: Química Nova (article, 2023-01-01)
Field: Chemistry — Organic Chemistry

APPLICATIONS OF NMR AND THEORETICAL CALCULATIONS TO STUDY THE O-H∙∙∙N INTRAMOLECULAR HYDROGEN BOND EFFECT ON THE CONFORMATIONAL EQUILIBRIUM OF CIS-3-N-ETHYLAMINOCYCLOHEXANOL AND CIS-3-N,N-DIETHYLAMINOCYCLOHEXANOL Textbooks show that in cis-1,3-disubstituted cyclohexane molecule, the conformer with the substituents in the diaxial positions is higher in energy and hence, it presents a low population in the conformational equilibrium. The diaxial conformer is destabilized by the repulsion between the substituent groups and the axial hydrogen atoms on the same side of the ring. This interaction is known as the 1,3-diaxial interaction. In this study, the solvent effect on the conformational equilibria of cis-3-N-ethylaminocyclohexanol (cis-3-EACOL) and cis-3-N,N-diethylaminocyclohexanol (cis-3-DEACOL) has been assessed through the spin-spin coupling constant (3JHH). The results show that the diaxial conformation of cis-3-EACOL decreases from 92% in CCl4 (∆Gee-aa = 1.48 kcal mol-1 ) to 10% in DMSO-d6 (∆Gee-aa = −1.31 kcal mol-1). For cis-3-DEACOL the diaxial conformer decreased from 36% in CCl4 (∆Gee-aa = −0.33 kcal mol-1) to 7% in Pyridine-d5 (∆Gee-aa = −1.55 kcal mol-1). The stabilization of the diaxial conformer in nonpolar solvents takes place due to the O-H···N intramolecular hydrogen bond, which overcomes the 1,3-diaxial steric interactions. Conformational isomerism ; Intramolecular force ; Chemistry ; Steric effects ; Hydrogen bond ; Substituent ; Cyclohexane ; Equilibrium constant ; Stereochemistry ; Population ; Cis–trans isomerism ; Crystallography ; Molecule ; Physical chemistry Chemical Reaction Mechanisms ; Molecular spectroscopy and chirality ; Molecular Spectroscopy and Structure
Authors: Simone Heilgeist | Oz Sahin | Ryo Sekine | Rodney A. Stewart
Source: Journal of Environmental Management (article, 2023-08-15)
Field: Materials Science — Materials Chemistry

Catching nano: Evaluating the fate and behaviour of nano-TiO2 in swimming pools through dynamic simulation modelling Environmental science ; Clarifier ; Nano- ; System dynamics ; Titanium dioxide ; Biochemical engineering ; Computer science ; Environmental engineering ; Engineering ; Chemical engineering Nanoparticles: synthesis and applications
Authors: Alexander Humeniuk | William J. Glover
Source: ChemRxiv (preprint, 2023-09-17)
Field: Chemistry — Physical and Theoretical Chemistry

Multistate, polarizable QM/MM embedding scheme based on the direct reaction field method: Solvatochromic shifts, analytical gradients and optimization of conical intersections in solution We recently introduced a polarizable embedding scheme based on an integral-exact reformulation of the direct reaction field method (IEDRF) that accounts for differential solvation of ground and excited states in QM/MM simulations. The polarization and dispersion interactions between the quantum-mechanical (QM) and molecular-mechanical (MM) regions are described by the DRF Hamiltonian, while the Pauli repulsion between explicitly treated QM electrons and the implicit electron density around MM atoms is modeled with effective core potentials. A single Hamiltonian is used for all electronic states, so that Born-Oppenheimer states belonging to the same geometry are orthogonal and state crossings are well-defined. In this work, we describe the implementation of the method using graphical processing unit acceleration in TeraChem, where it is combined with multiple electronic structure methods, including Hartree-Fock, Time-dependent Density Functional Theory, and Complete Active Space Self-Consistent Field. In contrast with older implementations of the DRF method, integrals of the polarization operators are evaluated exactly. Expressions for ingredients needed to construct analytical gradients and non-adiabatic coupling vectors are derived and tested by optimizing a conical intersection between two excited states in the presence of a polarizable solvent shell. The method is applied to estimating the solvent shifts of absorption energies of a series of donor-acceptor dyes having low-lying charge-transfer states. Even for a non-polar solvent such as n-hexane, the inclusion of its static polarizability leads to non-negligible shifts that improve the agreement with the positions of experimental absorption maxima measured in solution. Conical intersection ; Hamiltonian (control theory) ; Polarizability ; Chemistry ; Excited state ; QM/MM ; Density functional theory ; Solvation ; Configuration interaction ; Solvent models ; Ground state ; Molecular physics ; Quantum mechanics ; Atomic physics ; Physics ; Computational chemistry ; Molecular dynamics ; Molecule Photochemistry and Electron Transfer Studies ; Spectroscopy and Quantum Chemical Studies ; Free Radicals and Antioxidants
Authors: Daniel Qvarngård | Patrik Henelius
Source: arXiv (Cornell University) (preprint, 2023-11-07)
Field: Materials Science — Materials Chemistry

Classical spin models and basic magnetic interactions on 1/1-approximant crystals We study classical spin models on the 1/1 Tsai-type approximant lattice using Monte Carlo and mean-field methods. Our aim is to understand whether the phase diagram differences between Gd- and Tb-based approximants can be attributed to anisotropy induced by the crystal-electric field. To address this question, we treat Gd ions as Heisenberg spins and Tb ions as Ising spins. Additionally, we consider the presence of the RKKY interaction to replicate the experimentally observed correlation between magnetic properties and electron concentration. Surprisingly, our findings show that the transition between ferromagnetic and antiferromagnetic order remains unaltered by the anisotropy, even when accounting for the dipole interaction. We conclude that a more comprehensive model, extending beyond the free-electron gas RKKY interaction, is likely required to fully understand the distinctions between Gd- and Tb-based approximants. Our work represents a systematic exploration of the impact of anisotropy on the ground-state properties of classical spin models in quasicrystal approximants. Condensed matter physics ; Antiferromagnetism ; Spins ; Ising model ; Anisotropy ; Ferromagnetism ; RKKY interaction ; Physics ; Monte Carlo method ; Heisenberg model ; Spin (aerodynamics) ; Phase diagram ; Quantum mechanics ; Phase (matter) ; Mathematics Quasicrystal Structures and Properties ; Theoretical and Computational Physics ; X-ray Diffraction in Crystallography
Authors: Hamid Mehdipour | Peter Kratzer
Source: arXiv (Cornell University) (preprint, 2023-07-21)
Field: Materials Science — Materials Chemistry

First-principles Calculations of MoSeTe/WSeTe Bilayers: Stability, Phonons, Electronic Band Offsets, and Rashba Splitting Janus materials have attracted much interest due to their intrinsic electric dipole moment and Rashba band splitting. We show that, by building bilayers of MoSeTe and WSeTe with different chalcogen atom sequences and different stacking patterns, one can modulate the net dipole moment strength and the Rashba effect, as well as the band alignment of the MoSeTe/WSeTe bilayer. Type-II band alignment is found which can be exploited to create long-lived interlayer excitons. Moreover, it is shown that the atomic sequence and stacking play pivotal roles in the interlayer distance of MoSeTe/WSeTe and thus its electronic structure and vibrational, especially low-frequency, characteristics. The long-range dispersion forces between atoms are treated with a conventional additive pairwise, as well as a many-body-dispersion method. It is shown that under the many-body dispersion method, more clear and rational thermodynamic trends of bilayer stacking are realized and interface distances are estimated more accurately. Vibrational spectra of the bilayers are calculated using first-principles phonon calculations and the fingerprints of monolayer attraction and repulsion are identified. An anti-correlation between distance and the shearing mode frequency of the rigid monolayers is demonstrated which agrees well with experimental findings. The results suggest that the judicious selection of the atomic sequence and stacking helps to widen the scope of the low-dimensional materials by adding or enhancing properties for specific applications, e.g. for spintronics or valleytronics devices. Stacking ; Condensed matter physics ; Dipole ; Phonon ; Exciton ; Spintronics ; Materials science ; Monolayer ; Molecular physics ; Chemical physics ; Chemistry ; Nanotechnology ; Physics ; Ferromagnetism 2D Materials and Applications ; Advanced Thermoelectric Materials and Devices ; Heusler alloys: electronic and magnetic properties