jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yiming Pan | Fabio Caruso
Source: arXiv (Cornell University) (preprint, 2024-05-17)
Field: Materials Science — Materials Chemistry

Strain-induced activation of chiral-phonon emission in monolayer WS$_2$ We report a theoretical investigation of the ultrafast dynamics of electrons and phonons in strained monolayer WS$_2$ following photoexcitation. We show that strain substantially modifies the phase space for electron-phonon scattering, unlocking new relaxation pathways that are unavailable in the pristine monolayer. In particular, strain triggers a transition between distinct dynamical regimes of the non-equilibrium lattice dynamics characterized by the emission of chiral phonons under high strain and linearly-polarized phonons under low strain. For valley-polarized electronic excitations, this mechanism can be exploited to selectively activate the emission of chiral phonons -- phonons carrying a net angular momentum. Our simulations are based on state-of-the-art ab-initio methods and focus exclusively on realistic excitation and strain conditions that have already been achieved in recent experimental studies. Overall, strain emerges as a powerful tool for controlling chiral phonons emission and relaxation pathways in multivalley quantum materials. Monolayer ; Strain (injury) ; Phonon ; Materials science ; Condensed matter physics ; Chemical physics ; Chemistry ; Nanotechnology ; Physics 2D Materials and Applications ; Solid-state spectroscopy and crystallography ; Chalcogenide Semiconductor Thin Films
Authors: A. M. Thompson
Source: American Journal Of Pure And Applied Physics (article, 2024-08-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Applications of Spin Polarization in Nanomaterials and Devices Spin polarization is a key phenomenon in nanomaterials that plays a pivotal role in determining the electronic properties of materials. With the rapid growth of spintronics, spin-polarized nanomaterials are increasingly being used in novel devices such as magnetic sensors, memory storage devices, and quantum computing systems. This paper explores the applications of spin polarization in nanomaterials, highlighting their impact on device performance, particularly in the fields of spintronic devices, quantum computing, and energy harvesting systems. Additionally, we discuss the advancements in materials engineering that have enabled better spin polarization efficiency and the future directions of research in this field. Nanomaterials ; Spintronics ; Polarization (electrochemistry) ; Quantum dot ; Spin polarization ; Quantum ; Spin (aerodynamics) Heusler alloys: electronic and magnetic properties ; Magnetic properties of thin films ; Chemical and Physical Properties of Materials
Authors: Esther García‐Arroyo | Massimiliano Bartolomei | Marta I. Hernández | Tomás González‐Lezana | Massimo Mella | José Campos‐Martínez
Source: Physica Scripta (article, 2024-12-12)
Field: Materials Science — Materials Chemistry

Adsorption of molecular hydrogen on extended graphene prototypes decorated with sodium: a quantum-mechanical study Abstract This paper presents a study of sodium-decorated circumcircumcoronene, a large polycyclic aromatic hydrocarbon (PAH) regarded as a graphene prototype, and the complexes formed upon aggregation of hydrogen molecules on this substrate. Accurate force fields based on high level electronic structure calculations have been built using a rigid rotor model for the hydrogen molecules as well as a corresponding pseudo-atom approximation, aimed to pursue larger compounds where a simpler treatment could be helpful. Structural and energy features of the hydrogen adsorption have been then analyzed by means of quantum Monte Carlo methods. A large stabilization of the adsorption energy is found for up to four H 2 molecules attached to the alkali atom, in agreement with conclusions reached from previous studies on smaller Na-decorated PAHs. Adsorption patterns are examined in detail as the number of attached molecules is increased, comparing with results on smaller substrates and analyzing the effects of rotational orientation by contrasting the rigid rotor versus pseudo-atom approaches. Graphene ; Adsorption ; Molecule ; Materials science ; Hydrogen ; Hydrogen atom ; Atom (system on chip) ; Chemical physics ; Hydrocarbon ; Alkali metal ; Hydrogen bond ; Sodium ; Computational chemistry ; Nanotechnology ; Physical chemistry ; Chemistry ; Organic chemistry ; Computer science Hydrogen Storage and Materials ; Graphene research and applications ; Advanced Physical and Chemical Molecular Interactions
Authors: P K Sarga | H J Karthik | Swastibrata Bhattacharyya
Source: arXiv (Cornell University) (preprint, 2024-10-22)
Field: Materials Science — Materials Chemistry

Electronic and interfacial properties of 2D mxene/blue phosphorene heterostructures: impact of external strain for thermoelectric applications Building two-dimensional (2D) van der Waals (vdW) heterostructures and enhancing their properties through strain engineering unlocks new applications for their constituent materials. In this study, we present a comprehensive first-principles investigation of oxygen-functionalized MXene-based heterostructures (M$_2$CO$_2$ (M=Sc,Zr,Hf)/blue phosphorene), emphasizing their structural, electronic, and thermoelectric properties under the application of various types of strain. Our results indicate a reduction in band gap under strain and metallic transition for in-plane strain (uni- and bi-axial strain). Transition from type-I to type-II could be obtained for Hf$_2$CO$_2$/blueP and Zr$_2$CO$_2$/blueP heterostructure by applying strain, providing a method for their potential application in photocatalytic devices that require type-II band alignment for photogenerated charge separation. We observe a positive correlation between strain and thermoelectric efficiency under most conditions, with a significant enhancement in thermoelectric power factor (PF) and electronic figure of merit (ZTe) achievable in all heterostructures through strain engineering. Among the three heterostructures, Sc$_2$CO$_2$/blueP showed the maximum PF (ZTe) of $11.2 \times 10^{11}$ W/mK$^2$s (43.2) for 2% normal compressive (4% biaxial compressive) strain. These findings suggest that MX-ene/blueP heterostructures hold significant promise for applications in optoelectronics and high-temperature thermoelectric devices. Phosphorene ; Heterojunction ; Thermoelectric effect ; Materials science ; Strain (injury) ; Condensed matter physics ; Nanotechnology ; Optoelectronics ; Physics ; Thermodynamics ; Monolayer 2D Materials and Applications ; Advanced Thermoelectric Materials and Devices ; MXene and MAX Phase Materials
Authors: Zhandos A. Moldabekov | Thomas Gawne | Sebastian Schwalbe | Thomas R. Preston | Jan Vorberger | Tobias Dornheim
Source: arXiv (Cornell University) (preprint, 2024-03-26)
Field: Materials Science — Materials Chemistry

Ultrafast Heating Induced Suppression of $d$-band Dominance in the Electronic Excitation Spectrum of Cuprum The combination of isochoric heating of solids by free electron lasers (FEL) and in situ diagnostics by X-ray Thomson scattering (XRTS) allows for measurements of material properties at warm dense matter (WDM) conditions relevant for astrophysics, inertial confinement fusion, and material science. In the case of metals, the FEL beam pumps energy directly into electrons with the lattice structure of ions being nearly unaffected. This leads to a unique transient state that gives rise to a set of interesting physical effects, which can serve as a reliable testing platform for WDM theories. In this work, we present extensive linear-response time-dependent density functional theory (TDDFT) results for the electronic dynamic structure factor of isochorically heated copper with a face-centered cubic lattice. At ambient conditions, the plasmon is heavily damped due to the presence of $d$-band excitations, and its position is independent of the wavenumber. In contrast, the plasmon feature starts to dominate the excitation spectrum and has a Bohm-Gross type plasmon dispersion for temperatures $T \geq 4~{\rm eV}$, where the quasi-free electrons in the interstitial region are in the WDM regime. In addition, we analyze the thermal changes in the $d$-band excitations and outline the possibility to use future XRTS measurements of isochorically heated copper as a controlled testbed for WDM theories. Excitation ; Ultrashort pulse ; Dominance (genetics) ; Materials science ; Physics ; Optics ; Chemistry ; Laser ; Quantum mechanics Phase-change materials and chalcogenides
Authors: Wenhui Xu
Source: Science China Materials (article, 2024-02-28)
Field: Chemistry — Spectroscopy

Granting strength to aerogel fibers through encapsulation Aerogel ; Encapsulation (networking) ; Materials science ; Composite material ; Computer science ; Computer security Aerogels and thermal insulation ; Surface Modification and Superhydrophobicity ; Advanced Sensor and Energy Harvesting Materials
Authors: Sven P. Rudin
Source: OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (article, 2024-02-05)
Field: Materials Science — Materials Chemistry

Alternating layers of plutonium and lead or indium as surrogate for plutonium Elemental plutonium (Pu) assumes more crystal structures than other elements, plausibly due to bonding f electrons becoming non-bonding. Complex geometries hamper understanding of the transition in Pu, but calculations predict this transition in a system with simpler geometry: alternating layers either of plutonium and lead or of plutonium and indium. Here the transition occurs via a pairing-up of atoms within Pu layers. Calculations stepping through this pairing-up reveal valuable details of the transition, for example that the transition from bonding to non-bonding proceeds smoothly. Plutonium ; Indium ; Lead (geology) ; Radiochemistry ; Nuclear engineering ; Materials science ; Environmental science ; Chemistry ; Metallurgy ; Engineering ; Geology Nuclear Materials and Properties ; Radioactive element chemistry and processing ; Nuclear reactor physics and engineering
Authors: Akhil Kuriakose | Francesco P. Mezzapesa | Caterina Gaudiuso | Andrea Chiappini | Federico Picollo | Antonio Ancona | Ottavia Jedrkiewicz
Source: arXiv (Cornell University) (preprint, 2024-06-03)
Field: Materials Science — Materials Chemistry

Bessel beam fabrication of graphitic micro electrodes in diamond using laser bursts We present the fabrication of conductive graphitic microelectrodes in diamond by using pulsed Bessel beams in the burst mode laser writing regime. The graphitic wires are created in the bulk of a 500 μm thick monocrystalline HPHT diamond (with (100) orientation) perpendicular to the sample surface, without beam scanning or sample translation. In particular, the role of different burst features in the resistivity of such electrodes is investigated for two very different sub-pulse durations namely 200 fs and 10 ps, together with the role of thermal annealing. Micro-Raman spectroscopy is implemented to investigate the laser-induced crystalline modification, and the results obtained by using two different laser repetition rates, namely 20 Hz and 200 kHz, are compared. A comparison of the micro-Raman spectra and of the resistivity of the electrodes fabricated respectively with 10 ps single pulses and with bursts (of sub-pulses) of similar total duration has also been made, and we show that the burst mode writing regime allows to fabricate more conductive micro electrodes, thanks to the heat accumulation process leading to stronger graphitization. Moreover, the microfabrication of diamond by means of the longest available bursts (~ 46.7 ps duration) featured by 32 sub-pulses of 200 fs duration, with intra-burst time delay of 1.5 ps (sub-THz bursts), leads to graphitic wires with the lowest resistivity values obtained in this work, especially at low repetition rate such as 20 Hz. Indeed, micro electrodes with resistivity on the order of 0.01 Ω cm can be fabricated by Bessel beams in the burst mode regime even when the bursts are constituted by femtosecond laser sub-pulses, in contrast with the results of the standard writing regime with single fs pulses typically leading to less conductive micro electrodes. Fabrication ; Diamond ; Electrode ; Materials science ; Beam (structure) ; Laser beams ; Laser ; Optics ; Bessel function ; Bessel beam ; Optoelectronics ; Physics ; Composite material Diamond and Carbon-based Materials Research ; Laser Material Processing Techniques ; Laser-Ablation Synthesis of Nanoparticles
Authors: Samson Olalekan Odeyemi | Mokanmiyo Adedeji Olawale | Michael Oluwasegun Adisa | O. D. Atoyebi | Zainab Tolu Giwa
Source: Journal of Building Materials and Structures (article, 2024-06-30)
Field: Materials Science — Polymers and Plastics

Deflection-Based Numerical Evaluation of Steel, Bamboo Fibre, and Carbon Fibre Polymer Reinforced Portal Frame Reinforced concrete, a flexible building material, enjoys worldwide acceptance. Yet, its environmental footprint, especially regarding steel production, is substantial. The extensive mining of iron ore contributes to global warming, prompting the quest for greener alternatives. Bamboo fibre and carbon fibre were employed in sustainable industrial and construction practices to fulfill tensile requirements in reinforced concrete, effectively managing lateral loads on structural elements. This study aims to compare numerically the deflection resistance of portal frames reinforced with steel, bamboo fibre, and carbon fibre polymers using Abaqus version 6.14. The replacement of steel with carbon fibre within the portal frame exhibited comparable effectiveness to that of utilizing steel, whereas the introduction of bamboo fibre was observed to yield relatively diminished efficacy. However, differences between the results for steel, bamboo fibre, and carbon fibre are minimal, and carbon fibre performs similarly to steel. The maximum lateral movement values are 2.43 mm for steel, 2.68 mm for bamboo fibre, and 2.39 mm for carbon fibre. Bamboo ; Deflection (physics) ; Materials science ; Composite material ; Structural engineering ; Carbon steel ; Ultimate tensile strength ; Engineering Natural Fiber Reinforced Composites ; Bamboo properties and applications ; Structural Behavior of Reinforced Concrete
Authors: Jonathan Spring | Natalya S. Fedorova | Alexandru B. Georgescu | Alexander Vogel | Gabriele De Luca | Simon Jöhr | Cínthia Piamonteze | Marta D. Rossell | Jorge Íñiguez-González | Marta Gibert
Source: arXiv (Cornell University) (preprint, 2024-06-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Engineering the Magnetic Transition Temperatures and the Rare Earth Exchange Interaction in Oxide Heterostructures The properties of functional oxide heterostructures are strongly influenced by the physics governing their interfaces. Modern deposition techniques allow us to accurately engineer the interface physics through the growth of atomically precise heterostructures. This enables minute control over the electronic, magnetic, and structural characteristics. Here, we investigate the magnetic properties of tailor-made superlattices employing the ferromagnetic and insulating double perovskites RE$_2$NiMnO$_6$ (RE = La, Nd), featuring distinct Curie temperatures. Adjusting the superlattice periodicity at the unit cell level allows us to engineer their magnetic phase diagram. Large periodicity superlattices conserve the individual para- to ferromagnetic transitions of the La$_2$NiMnO$_6$ and Nd$_2$NiMnO$_6$ parent compounds. As the superlattice periodicity is reduced, the Curie temperatures of the superlattice constituents converge and, finally, collapse into one single transition for the lowest period samples. This is a consequence of the magnetic order parameter propagating across the superlattice interfaces, as supported by a minimal Landau theory model. Further, we find that the Nd-Ni/Mn exchange interaction can be enhanced by the superlattice interfaces. This leads to a field-induced reversal of the Nd magnetic moments, as confirmed by synchrotron X-ray magnetic circular dichroism measurements and supported by first-principles calculations. Our work demonstrates how superlattice engineering can be employed to fine-tune the magnetic properties in oxide heterostructures and broadens our understanding of magnetic interfacial effects. Rare earth ; Heterojunction ; Oxide ; Condensed matter physics ; Transition (genetics) ; Materials science ; Engineering physics ; Chemistry ; Physics ; Metallurgy Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics ; Rare-earth and actinide compounds
Authors: Annabell Martin | Pablo Rivera Fuentes
Source: CHIMIA International Journal for Chemistry (article, 2024-04-24)
Field: Chemistry — Organic Chemistry

A Baldwin-favored Cyclization Inspires the Development of Fluorogenic Polymethine Dyes for Bioimaging Fluorescence imaging is an invaluable tool to study biological processes, and fluorogenic dyes are crucial to enhance cell permeability and target intracellular structures with high specificity. Polymethine dyes are vitally important fluorophores in single-molecule localization microscopy and in vivo imaging, but their use in live cells has been limited by high background fluorescence and low membrane permeability. Here, we present a general strategy to transform polymethine compounds into fluorogenic dyes by implementing a 5-exo-trig ring-closure. This method provides access to bright, fluorogenic polymethine dyes with emissions across the visible and near-infrared spectrum. Fluorescence ; Chemistry ; Membrane permeability ; Biophysics ; Nanotechnology ; Live cell imaging ; Fluorescence-lifetime imaging microscopy ; Fluorescence microscope ; Intracellular ; Membrane ; Photochemistry ; Materials science ; Cell ; Biochemistry ; Biology ; Optics Click Chemistry and Applications ; Advanced Fluorescence Microscopy Techniques ; Nanoplatforms for cancer theranostics
Authors: V. Stepkova | J. Hlinka
Source: arXiv (Cornell University) (preprint, 2024-10-08)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Creation, annihilation and transport of nonmagnetic antiskyrmions within Ginzburg-Landau-Devonshire model Atomistic model calculations recently revealed that the polarization pattern at the cross-section through nanoscale ferroelectric nanodomains in rhombohedral barium titanate shows a clear antiskyrmion attributes such as the net invariant topological charge of minus two. The present work confirms that these topological defects also exist as local minima in the discretized Ginzburg-Landau-Devonshire model, which is widely used in the phase-field modeling studies. We explore by phase-field simulations how an electric field can be used to create or move antiskyrmions within a monodomain ferroelectric matrix. The process of the field-induced antiskyrmion annihilation reveals the existence of a discrete ladder of intermediate antiskyrmion states with distinct radii but common symmetry, topology and geometrical properties. Annihilation ; Physics ; Condensed matter physics ; Statistical physics ; Nuclear physics Magnetic and transport properties of perovskites and related materials ; Rare-earth and actinide compounds ; Physics of Superconductivity and Magnetism
Authors: А. В. Гончаренко | V. M. Silkin
Source: Photonics (article, 2024-12-18)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Broadening the Bandwidth of Epsilon-Near-Zero Metamaterials with Embedded Square Frames A narrow frequency bandwidth of epsilon-near-zero metamaterials limits the use of many optical, microwave, and electronic devices. In this paper, we propose a recipe to broaden the operational bandwidth by employing a structure of properly tailored square frames nested within each other. To illustrate this effect, we derive the effective permittivity for the considered frame geometry. Then, we show that combining constituent materials with loss and materials with gain enables us to achieve the effective permittivity over a frequency band as small as desired. This technique may prove valuable for various applications including invisibility cloaks, camouflage, shielding, and sensorics. Metamaterial ; Bandwidth (computing) ; Zero (linguistics) ; Square (algebra) ; Optics ; Physics ; Optoelectronics ; Computer science ; Telecommunications ; Mathematics ; Geometry Metamaterials and Metasurfaces Applications ; Antenna Design and Analysis ; Advanced Antenna and Metasurface Technologies
Authors: Zhihao Liu | Shengnan Zhang | Zhong Fang | Hongming Weng | Quansheng Wu
Source: arXiv (Cornell University) (preprint, 2024-01-26)
Field: Materials Science — Electronic, Optical and Magnetic Materials

A combined First-principles and Boltzmann transport theory methodology for studying magnetotransport in magnetic materials Unusual magnetotransport behaviors, such as temperature-dependent negative magnetoresistance (MR) and bowtie-shaped MR, have puzzled us for a long time. Although several mechanisms have been proposed to explain these phenomena, the absence of comprehensive quantitative calculations has made these explanations less convincing. In our work, we introduce a methodology to study magnetotransport behaviors in magnetic materials. This approach integrates the anomalous Hall conductivity induced by the Berry curvature, with a multi-band ordinary conductivity tensor, employing a combination of first-principles calculations and semi-classical Boltzmann transport theory. Our method also incorporates the temperature dependence of the relaxation time and the anomalous Hall conductivity, as well as the field dependence of the anomalous Hall conductivity. We initially test this approach on models, obtaining distinct behaviors of magnetoresistance and Hall resistivity across several types of magnetic materials, and then apply it to a Weyl semimetal, Co3Sn2S2. The results, which align well with experimental observations in terms of magnetic field and temperature dependencies, demonstrate the efficacy of our approach. This methodology provides a comprehensive and efficient means to understand the underlying mechanisms of the unusual complex behaviors observed in magnetotransport measurements in magnetic materials. Condensed matter physics ; Materials science ; Physics Magnetic Properties and Applications ; Magnetic properties of thin films ; Magnetic Field Sensors Techniques