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Multistate Control of Nonlinear Photocurrents in Optoferroelectrics via phase manipulation of light field

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arXiv 2025年

作者： Kazempour, Ali Sisakht, Esmaeil Taghizadeh Okyay, Mahmut Sait Jiang, Xiao Sato, Shunsuke Park, Noejung Department of physics Payame Noor University PO BOX Tehran119395-3697 Iran Department of Physics Ulsan National Institute of Science and Technology Ulsan689-798 Korea Republic of Materials Science and Engineering Program Department of Chemical and Environmental Engineering University of California-Riverside RiversideCA92521 United States Center for Computational Sciences University of Tsukuba Tsukuba305-8577 Japan

Ultrafast optical control of ferroelectricity based on short and intense light can be utilized to achieve accurate manipulations of ferroelectric materials, which may pave a basis for future breakthrough in nonvolatile memories. Here, we demonstrate that phase manipulation of electric field in the strong field sub-cycle regime induces a nonlinear injection current, efficiently coupling with the topology of band structure and enabling dynamic reversal of both current and polarization. Our time-dependent first-principles calculations reveal that tuning the phase of linearly or circularly polarized light through time-varying chirp, or constant carrier envelop phases within sub-laser-cycle dynamics effectively breaks the time-reversal symmetry, allowing the control over current and electronic polarization reversal over multi-ferroelectric states. Our time- and momentum-resolved transverse current analysis reveal the significance of Berry curvature higher order poles in the apparent association between the odd (even) orders of Berry curvature multipoles to odd (even) pseudo-harmonics in driving polarization dynamics reversal. We suggest that these phase manipulations of short pulse waveform may lead to unprecedented accurate control of nonlinear photocurrents and polarization states, which facilitate the development of precise ultrafast opto-ferroelectric devices. © 2025, CC BY.

关键词： Ferroelectricity

Enhancing the Properties of Polyester Composites Using Unidirectional Acetylated Fibers from Luffa Cylindrica

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Enhancing the Properties of Polyester Composites Using Unidi...

Symposium on Natural Fibers and Biocomposites: A Sustainable Solution, 2025, held as part of the TMS Annual Meeting and Exhibition, TMS 2025

作者： de Melo, Eduarda C. R. Amaral, Heliane R. dos Silva, Roseméri B. S. Cândido, Verônica S. Lopes, Felipe P. D. Monteiro, Sergio N. Oliveira, Michel P. Forest and Wood Sciences Department Federal University of Espírito Santo Jeronimo Monteiro Vitória29550-000 Brazil Laboratory of Carbon and Ceramic Materials Department of Physics Federal University of Espírito Santo ES Vitória29075-910 Brazil Engineering of Natural Resources of the Amazon Program Federal University of Para PA Belem67030-007 Brazil Rio de Janeiro22290-270 Brazil Advanced Materials Laboratory State University of the North of Rio de Janeiro Darcy Ribeiro—UENF Av Alberto Lamego 2000 CEP 28013-602 RJ Campos dos Goytacazes Brazil

ISBN: (纸本)9783031811890

Polymeric compositesComposite reinforced by lignocellulosic fibersLignocellulosic fibers are an eco-friendly option for various applications that utilize the benefits of natural fibersNatural fibers and polymersPolymers to create materials with improved mechanical propertiesMechanical property and minimal environmental impactImpact. In this study, we acetylated unidirectional fibers from Luffa cylindrica and incorporated them into a polyester matrix. X-ray diffraction and Fourier-transform infrared spectroscopy analyses confirmed the success of the acetylation process, replacing hydroxyl groups with acetyl groups. Moreover, thermal analysis showed that the acetylated fibers had no mass loss up to 200 °C, indicating their hydrophobic nature. Scanning electron microscopy displayed an excellent interface between the acetylated fibers and the polymeric matrix. The Charpy impactImpact resistance for the acetylated fibers showed a remarkable 1865% increase compared to pure polyester. Additionally, the compositeComposite with acetylated fibers absorbed only 2.54% of water. These results demonstrate that lignocellulosic fibersLignocellulosic fibers’ in situ acetylation process offers a more sustainable alternative to synthetic fibers. © The Minerals, Metals & materials Society 2025.

关键词： Natural fibers

Observation of mechanical kink control and generation via phonons

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arXiv 2025年

作者： Qian, Kai Cheng, Nan Serafin, Francesco Sun, Kai Theocharis, Georgios Mao, Xiaoming Boechler, Nicholas Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA92093 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Physics and Materials Science University of Luxembourg 2 Avenue de l’Universite L Esch-sur-Alzette4365 Luxembourg CNRS Le Mans Université France Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States

Kinks (or domain walls) are localized transitions between distinct ground states associated with a topological invariant, and are central to many phenomena across physics, from condensed matter to cosmology. While phonon (i.e., small-amplitude vibration) wave packets have been theorized to deterministically interact with kinks and initiate their movement, this interaction has remained elusive in experiments, where only uncontrollable stochastic kink motion generated by thermal phonons or dislocation glide by low-frequency quasi-static loading have been observed. This is partly because all physical systems that support kinks are, at some level, discrete, making deterministic phonon control of kinks extremely challenging due to the existence of Peierls-Nabarro (PN) barrier. Here, we demonstrate, for the first time, experimental observation of phonon-mediated control and generation of mechanical kinks, which we enable using a topological metamaterial that constitutes an elastic realization of the Kane-Lubensky chain model. Our metamaterial overcomes the PN barrier by supporting a single, topologically protected kink that requires zero energy to form and move. Using simulations that show close agreement with our experimental observations, we also reveal unique dynamics of phonon interplay with highly discrete kinks, including long-duration motion and a continuous family of internal modes, features absent in other discrete nonlinear systems. This work introduces a new paradigm for topological kink control, with potential applications in material stiffness tuning, shape morphing, locomotion, and robust signal transmission. © 2025, CC BY-NC-ND.

关键词： Stochastic systems

TiCu-CMC/PDA coatings with long-term antimicrobial activity and cytocompatibility for surface engineering of implants

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Surface and Coatings Technology 2025年 509卷

作者： Zheng, Xiaosong Jiang, Yehao Zheng, Fazhan Xiang, Long Zhou, Lili Liang, Wenlang Huang, Nan Leng, Yongxiang Akhavan, Behnam Jing, Fengjuan Institute of Biomedical Engineering College of Medicine Southwest Jiaotong University Sichuan Chengdu610031 China Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University Chengdu610031 China School of Engineering University of Newcastle CallaghanNSW2308 Australia Precision Medicine Program New Lambton HeightsNSW2305 Australia School of Biomedical Engineering University of Sydney SydneyNSW2006 Australia School of Physics University of Sydney SydneyNSW2006 Australia Sydney Nano Institute University of Sydney SydneyNSW2006 Australia

Long-term antibacterial effects and favourable biocompatibility are crucial to sustaining the long-term application of medical devices such as cardiac implantable devices, orthopedic devices, hernia meshes, and catheters. This study reports the development of sodium carboxymethyl cellulose/polydopamine films on Ti[sbnd]Cu coatings (TiCu-CMC/PDA) with long-term antimicrobial effects and cytocompatibility for surface engineering of implants. The TiCu-CMC/PDA coatings demonstrate sustained antimicrobial efficacy, maintaining bacterial inhibition rates above 99.6 % after aging in simulated body fluid (SBF) at 37 °C for 60 days. This remarkable antibacterial performance is primarily driven by the controlled release of copper ions during aging, complemented by surface copper's contribution to antimicrobial effects. Further, the TiCu-CMC/PDA coatings exhibit high cell viability and proliferation with negligible cytotoxicity, attributed to the regulated copper ion release. However, the endothelial cell viability on TiCu-CMC/PDA coatings decreased with aging due to the formation of copper ion complexes and CuO/Cu(OH)2, as well as increased surface roughness and hydrophilicity over time. The technology offers a simple and controllable approach to fabricating TiCu-CMC/PDA coatings, providing a pathway for the design of long-term antibacterial biomedical devices, including cardiovascular and orthopedic implants. © 2024

关键词： Antibiotics

Supplementary information for "Low-loss silicon nitride Kerr-microresonators fabricated with metallic etch masks via metal lift-off"

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arXiv 2025年

作者： Colación, Gabriel M. Rukh, Lala Buck, Franco Drake, Tara E. Optical Science & Engineering Program University of New Mexico AlbuquerqueNM87106 United States Center for High Technology Materials University of New Mexico AlbuquerqueNM87106 United States Department of Physics & Astronomy University of New Mexico AlbuquerqueNM87106 United States

Stoichiometric silicon nitride has emerged as a widely used integratedphotonic material owing to its high index of refraction, nonlinear opticalproperties, and broad transparency window spanning visible to mid-IRfrequencies. However, silicon nitride is generally more resistant to reactiveion etching than are typical etch masks made of polymer-based resist. Thisnecessitates resist layers that are significantly thicker than the siliconnitride and results in mask patterns which are tall and narrow. Thesehigh-aspect-ratio patterns inhibit the plasma transport of reactive ionetching, which leads to difficulties in accurately reproducing dimensions andcreating well-defined, vertical waveguide sidewalls. In this work, we overcomethese challenges by developing a metallic etch mask that provides a 30:1nitride-to-metal etch rate ratio, representing a near 20-fold reduction in therequired mask thickness. We demonstrate the quality of this technique byetching microring resonators with near-vertical waveguide sidewalls andintrinsic quality factors of over 1 million. Leveraging the low optical loss ofour resonators, we generate optical frequency combs with more than an octave ofbandwidth and dual dispersive waves. These results establish metal lift-off asa viable and easy-to-implement technique capable of producing low optical losswaveguides. © 2025, CC BY.

关键词： Aspect ratio

Visualizing Field-free Deterministic Magnetic Switching of all–van der Waals Spin-Orbit Torque System Using Spin Ensembles in Hexagonal Boron Nitride

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arXiv 2025年

作者： Zhang, Xi Zhou, Jingcheng Hu, Chaowei Deng, Kuangyin Wang, Chuangtang Agarwal, Nishkarsh Jin, Hanshang Al-Matouq, Faris A. Xu, Stelo Trivedi, Roshan S. Li, Senlei Rathi, Sumedh Lu, Hanyi Jiang, Zhigang Taufour, Valentin Hovden, Robert Zhao, Liuyan Cheng, Ran Xu, Xiaodong Chu, Jiun-Haw Du, Chunhui Rita Wang, Hailong School of Physics Georgia Institute of Technology AtlantaGA30332 United States Department of Physics University of Washington SeattleWA98105 United States Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California DavisCA95616 United States Department of Physics University of California San Diego La Jolla CA92093 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California RiversideCA92521 United States Department of Materials Science and Engineering University of Washington SeattleWA98105 United States

Recently, optically active spin defects embedded in van der Waals (vdW) crystals have emerged as a transformative quantum sensing platform to explore cutting-edge materials science and quantum physics. Taking advantage of excellent solid-state integrability, this new class of spin defects can be arranged in controllable nanoscale proximity of target materials in vdW heterostructures, showing great promise for improving spatial resolution and field sensitivity of current sensing technologies. Building on this state-of-the-art measurement platform, here we report hexagonal boron nitride-based quantum imaging of field-free deterministic magnetic switching of room-temperature two-dimensional magnet Fe3GaTe2 in an all-vdW spin-orbit torque (SOT) system. By visualizing SOT-driven variations of nanoscale Fe3GaTe2 magnetic stray field profile under different conditions, we have revealed how the observed magnetic switching evolves from deterministic to indeterministic behavior due to the interplay between out-of-plane spins, in-plane spins and Joule heating. This understanding, which is otherwise difficult to access by conventional transport measurements, offers valuable insights on material design, testing, and evaluation of next-generation vdW spintronic devices. Copyright © 2025, The Authors. All rights reserved.

关键词： Van der Waals forces

Spin pumping mechanism in Py/SnTe bilayers: An approach through the magnetoimpedance effect

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Journal of Alloys and Compounds 2025年 1031卷

作者： de Morais, A. Souza, E.C. de Silva, A.L. Gamino, M. da Silva, E.F. Ferreira, A. Vaz, F. Lopes, C. Bohn, F. Correa, M.A. Postgraduate Program in Materials Science and Engineering Federal University of Rio Grande do Norte RN Natal 59078-970 Brazil Physics Department Federal University of Rio Grande do Norte RN Natal 59075-000 Brazil Physics Department Federal University of Pernambuco PE Recife 50670-901 Brazil Physics Centre of Minho and Porto Universities (CF-UM-UP) University of Minho 4710-057 Portugal LaPMET - Laboratory of Physics for Materials and Emergent Technologies University of Minho 4710-057 Portugal

Different techniques addressing magnetization dynamics are helpful to estimate parameters of a ferromagnetic thin film nanostructure in the field of spintronics, including Gilbert damping parameter (α_G), spin pumping contributions (α_SP), two magnons scattering (α_TMS), spin mixing conductance (G_eff) and others. When considering a bilayer structure, the non-ferromagnetic layer effects need to be carefully selected to tailor an effective spintronic response. Here, the magnetization dynamics are explored in Ni₈₁Fe₁₉(Py)/Ag and Ni₈₁Fe₁₉(Py)/SnTe nanostructures and report the spin mixing conductance from magnetoimpedance experiments. The results are interpreted by considering structural and magnetic characterizations. The spin mixing conductance is estimated as G_eff (Py/Ag) = 1.13×10¹⁴ cm⁻² and G_eff (Py/SnTe) = 18.05 ×10¹⁴ cm⁻², revealing the significant enhancement of G_eff when the SnTe acts as a cap layer, indicating that SnTe is a good spin sink. © 2025 Elsevier B.V.

关键词： Damping mechanisms Magnetoimpedance SnTe Spin pumping Spintronics

Emulating complex synapses using interlinked proton conductors

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Physical Review Applied 2025年第1期23卷 014027-014027页

作者： Lifu Zhang Ji-An Li Yang Hu Jie Jiang Rongjie Lai Marcus K. Benna Jian Shi Department of Materials Science and Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA Neurosciences Graduate Program University of California San Diego La Jolla California 92093 USA Department of Mathematics Purdue University West Lafayette Indiana 47907 USA Department of Neurobiology School of Biological Sciences University of California at San Diego La Jolla California 92093 USA Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA

In terms of energy efficiency and computational speed, neuromorphic electronics based on nonvolatile memory devices are expected to be one of most promising hardware candidates for future artificial intelligence (AI). However, catastrophic forgetting, networks rapidly overwriting previously learned weights when learning new tasks, remains a pivotal obstacle in either digital or analog AI chips for unleashing the true power of brainlike computing. To address catastrophic forgetting in the context of online memory storage, a complex synapse model (the Benna-Fusi model) was proposed recently [M. K. Benna and S. Fusi, Nat. Neurosci. 19, 1697 (2016)], the synaptic weight and internal variables of which evolve following diffusion dynamics. In this work, by designing a proton transistor with a series of charge-diffusion-controlled storage components, we have experimentally realized the Benna-Fusi artificial complex synapse. Memory consolidation from coupled storage components is revealed by both numerical simulations and experimental observations. Different memory timescales for the complex synapse are engineered by the diffusion length of charge carriers and the capacity and number of coupled storage components. The advantages of the demonstrated complex synapse for both memory capacity and memory consolidation are revealed by neural network simulations of face-familiarity detection. Our experimental realization of the complex synapse suggests a promising approach to enhance memory capacity and to enable continual learning.

关键词： Nonvolatile storage

Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells