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arXiv 2021年

作者： Doustkhah, Esmail Tahawy, Rafat Simon, Ulla Tsunoji, Nao Ide, Yusuke Hanaor, Dorian A.H. Hussein N. Assadi, M. 1-1 Namiki Tsukuba Ibaraki305-0044 Japan Fachgebiet Keramische Werkstoffe Technische Universität Berlin Berlin10623 Germany Graduate School of Advanced Science and Engineering Applied Chemistry Program Hiroshima University 1-4-1 Kagamiyama Higashi-Hiroshima739-8527 Japan School of Materials Science and Engineering The University of New South Wales SydneyNSW2052 Australia

Microporous organosilicas assembled from polysilsesquioxane (POSS) building blocks are promising materials that are yet to be explored in-depth. Here, we investigate the processing and molecular structure of bispropylurea bridged POSS (POSS-urea), synthesised through the acidic condensation of 1,3-bis(3-(triethoxysilyl)propyl)urea (BTPU). Experimentally, we show that POSS-urea has excellent functionality for molecular recognition toward acetonitrile with an adsorption level of 74 mmol/g, which compares favourably to MOFs and zeolites, with applications in volatile organic compounds (VOC). The acetonitrile adsorption capacity was 132-fold higher relative to adsorption capacity for toluene, which shows the pores are highly selective towards acetonitrile adsorption due to their size and arrangement. Theoretically, our tight-binding density functional and molecular dynamics calculations demonstrated that this BTPU based POSS is microporous with an irregular placement of the pores. Structural studies confirm maximal pore sizes of ~ 1 nm, with POSS cages possessing an approximate edge length of ~ 3.16 Å. © 2021, CC BY.

关键词： Urea

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Unifying femtosecond and picosecond single-pulse magnetic switching in Gd-Fe-Co

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Physical Review B 2021年第10期103卷 104422-104422页

作者： F. Jakobs T. A. Ostler C.-H. Lambert Y. Yang S. Salahuddin R. B. Wilson J. Gorchon J. Bokor U. Atxitia Dahlem Center for Complex Quantum Systems and Fachbereich Physik Freie Universität Berlin 14195 Berlin Germany Département de Physique Universitè de Liége (B5) B-4000 Liége Belgium College of Business Technology and Engineering Sheffield Hallam University Howard Street Sheffield S1 1WB United Kingdom Department of Electrical Engineering and Computer Sciences University of California Berkeley California 94720 USA Department of Materials Science and Engineering University of California Berkeley California 94720 USA Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Department of Mechanical Engineering and Materials Science and Engineering Program University of California Riverside California 92521 USA

Many questions are still open regarding the physical mechanisms behind the magnetic switching in Gd-Fe-Co alloys by single optical pulses. Phenomenological models suggest a femtosecond scale exchange relaxation between sublattice magnetization as the driving mechanism for switching. The recent observation of thermally induced switching in Gd-Fe-Co by using both several picosecond optical laser pulse as well as electric current pulses has questioned this previous understanding. This has raised the question of whether or not the same switching mechanics are acting at the femtosecond and picosecond scales. In this work, we aim at filling this gap in the understanding of the switching mechanisms behind thermal single-pulse switching. To that end, we have studied experimentally thermal single-pulse switching in Gd-Fe-Co alloys, for a wide range of system parameters, such as composition, laser power, and pulse duration. We provide a quantitative description of the switching dynamics using atomistic spin dynamics methods with excellent agreement between the model and our experiments across a wide range of parameters and timescales, ranging from femtoseconds to picoseconds. Furthermore, we find distinct element-specific damping parameters as a key ingredient for switching with long picosecond pulses and argue that switching with pulse durations as long as 15 ps is possible due to a low damping constant of Gd. Our findings can be easily extended to speed up dynamics in other contexts where ferrimagnetic Gd-Fe-Co alloys have been already demonstrated to show fast and energy-efficient processes, e.g., domain-wall motion in a track and spin-orbit torque switching in spintronics devices.

关键词： Demagnetization Magnetic interactions Magnetic order Magnetism Spin dynamics Ultrafast magnetic effects

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Electronic excitations of α−Fe2O3 heteroepitaxial films measured by resonant inelastic x-ray scattering at the Fe L edge

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Physical Review B 2022年第7期105卷 075101-075101页

作者： David S. Ellis Ru-Pan Wang Deniz Wong Jason K. Cooper Christian Schulz Yi-De Chuang Yifat Piekner Daniel A. Grave Markus Schleuning Dennis Friedrich Frank M. F. de Groot Avner Rothschild Department of Materials Science and Engineering Technion-Israel Institute of Technology Haifa 32000 Israel Department of Physics University of Hamburg Luruper Chaussee 149 22761 Hamburg Germany Dynamics and Transport in Quantum Materials Helmholtz-Zentrum Berlin für Materialen und Energie Albert-Einstein-Strasse 15 12489 Berlin Germany Chemical Sciences Division Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Advanced Light Source Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA The Nancy & Stephen Grand Technion Energy Program (GTEP) Technion-Israel Institute of Technology Haifa 32000 Israel Department of Materials Engineering and Ilse Katz Institute for Nanoscale Science and Technology Ben Gurion University of the Negev Be'er Sheva 8410501 Israel Institute for Solar Fuels Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Hahn-Meitner-Platz 1 14109 Berlin Germany Department of Inorganic Chemistry and Catalysis Debye Institute of Nanomaterials Science Utrecht University Universiteitsweg 99 3584 CG Utrecht Netherlands

Resonant inelastic x-ray scattering (RIXS) spectra of hematite (α−Fe2O3) were measured at the Fe L3 edge for heteroepitaxial thin films which were undoped and doped with 1% Ti, Sn, or Zn, in the energy-loss range in excess of 1 eV to study electronic transitions. The spectra were measured for several momentum transfers q, conducted at both low temperature (T=14 K) and room temperature. While we cannot rule out dispersive features possibly owing to propagating excitations, the coarse envelopes of the general spectra did not appreciably change shape with q, implying that the bulk of the observed L-edge RIXS intensity originates from (mostly) nondispersive ligand field excitations. Summing the RIXS spectra over q and comparing the results at T=14 K to those at T=300 K revealed pronounced temperature effects, including an intensity change and energy shift of the ≈1.4 eV peak, a broadband intensity increase of the 3–4 eV range, and higher energy features. The q-summed spectra and their temperature dependencies are virtually identical for nearly all of the samples with different dopants, save for the temperature dependence of the Ti-doped sample's spectrum, which we attribute to being affected by a large number of free charge carriers. Comparing with magnetization measurements for different temperatures and dopings likewise did not show a clear correlation between the RIXS spectra and the magnetic ordering states. To clarify the excited states, we performed spin multiplet calculations which were in excellent agreement with the RIXS spectra over a wide energy range and provide detailed electronic descriptions of the excited states. The implications of these findings to the photoconversion efficiency of hematite photoanodes is discussed.

关键词： Electronic structure Energy materials Strongly correlated systems Crystal-field theory Energy-dispersive x-ray spectroscopy

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Cold atmospheric plasma-enabled platelet vesicle incorporated iron oxide nano-propellers for thrombolysis

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materials Today Bio 2023年 23卷 100876页

作者： Jheng, Pei-Ru Chiang, Chia-Che Kang, Jiunn-Horng Fan, Yu-Jui Wu, Kevin C.-W. Chen, Yan-Ting Liang, Jia-Wei Bolouki, Nima Lee, Jyh-Wei Hsieh, Jang-Hsing Chuang, Er-Yuan Graduate Institute of Nanomedicine and Medical Engineering Graduate Institute of Biomedical Materials and Tissue Engineering Institute of Biomedical Optomechatronics International Ph.D. Program in Biomedical Engineering School of Biomedical Engineering College of Biomedical Engineering Professional Master Program in Artificial Intelligence in Medicine College of Medicine Taipei Medical University Taipei11031 Taiwan Department of Physical Medicine and Rehabilitation Taipei Medical University Hospital Taipei Taiwan Institute of Biomedical Engineering & Nanomedicine National Health Research Institute Keyan Road Zhunan Miaoli City350 Taiwan Department of Chemical Engineering National Taiwan University No.1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan Department of Plasma Physics and Technology Faculty of Science Masaryk University Brno Czech Republic Center for Plasma and Thin Film Technologies Ming Chi University of Technology New Taipei City Taiwan Department of Materials Engineering Ming Chi University of Technology New Taipei City Taiwan Cell Physiology and Molecular Image Research Center Taipei Medical University-Wan Fang Hospital Taipei11696 Taiwan

A new approach to treating vascular blockages has been developed to overcome the limitations of current thrombolytic therapies. This approach involves biosafety and multimodal plasma-derived theranostic platelet vesicle incorporating iron oxide constructed nano-propellers platformed technology that possesses fluorescent and magnetic features and manifold thrombus targeting modes. The platform is capable of being guided and visualized remotely to specifically target thrombi, and it can be activated using near-infrared phototherapy along with an actuated magnet for magnetotherapy. In a murine model of thrombus lesion, this proposed multimodal approach showed an approximately 80 % reduction in thrombus residues. Moreover, the new strategy not only improves thrombolysis but also boosts the rate of lysis, making it a promising candidate for time-sensitive thrombolytic therapy. © 2023 The Authors

关键词： Infrared devices

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Effects of sodium alginate-poly(acrylic acid) cross-linked hydrogel beads on soil conditioner in the absence and presence of phosphate and carbonate ions

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Case Studies in Chemical and Environmental engineering 2024年 9卷

作者： Hidayat, Endar Sarbani, Nur Maisarah Mohamad Lahiri, Sudip Kumar Samitsu, Sadaki Yonemura, Seiichiro Mitoma, Yoshiharu Harada, Hiroyuki Graduate School of Comprehensive Scientific Research Program in Biological System Sciences Prefectural University of Hiroshima Shobara 727-0023 Japan Department of Life System Science Faculty of Bioresources Science Prefectural University of Hiroshima Shobara 727-0023 Japan Data-driven Polymer Design Group Research Center for Macromolecules and Biomaterials National Institute for Materials Science 1−2−1 Sengen Tsukuba 305-0047 Japan Department of Mechanical & Industrial Engineering University of Toronto Toronto M5S 3G8 ON Canada Faculty of Allied Health Sciences Chettinad Hospital and Research Institute Chettinad Academy of Research and Education Tamil Nadu Kelambakkam 603103 India

Hydrogel beads, composed of polymers, possess the ability to absorb substantial quantities of water simultaneously and gradually release it in dry conditions. In this work, hydrogel beads were synthesized using sodium alginate (S-Alg) and poly (acrylic acid) (P-Acc), either in the absence or presence of phosphate (PO₄ ³⁻) (S-Alg/P-Acc@PO₄ ³⁻) and carbonate (CO₃ ²⁻) anionic ions (S-Alg/P-Acc@CO₃ ²⁻). Subsequently, these beads were crosslinked with Ca²⁺ ions. The scanning electron microscopy (SEM) images demonstrated that the presence of anionic ions has an impact on the structure of the hydrogel beads and enhances porosity expansion while concurrently reducing the concentration of carboxyl (COOH) groups. The hydrogel beads exhibited a great swelling behavior, with S-Alg/P-Acc@CO₃ ²⁻ capable of absorbing up to 73.5 % of water in acidic conditions, but decreased under neutral and basic conditions. Soil water loss (SWL) experiments confirmed the ability of hydrogel beads to retain water in the soil. Additionally, observations of soil characteristics after a 14-day treatment revealed no significant difference in pH and C/N ratio (P-value <0.05). However, soil's available Fe and N–NO₃ ^- significantly reduced (P-value <0.05) while substantially promoting soil N–NH₄ ⁺, available phosphorus (P), cation exchange capacity (CEC), soil organic carbon (SOC), and exchangeable cation (Ca²⁺, K⁺ and Mg²⁺). The presence of hydroxyl (-OH) and –COOH groups was found to be crucial for enhancing soil properties. © 2024 The Authors

关键词： Anionic ions Hydrogel beads Poly (acrylic acid) Sodium alginate Soil characteristics Soil water retention Swelling

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Room-temperature quantum sensing with photoexcited triplet electrons in organic crystals

arXiv

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arXiv 2024年

作者： Singh, Harpreet D’Souza, Noella Zhong, Keyuan Druga, Emanuel Oshiro, Julianne Blankenship, Brian Montis, Riccardo Reimer, Jeffrey A. Breeze, Jonathan D. Ajoy, Ashok Department of Chemistry University of California Berkeley BerkeleyCA94720 United States Department of Physics Guru Nanak Dev University Punjab Amritsar143005 India Chemical Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Chemical and Biomolecular Engineering University of California BerkeleyCA94720 United States Department of Pure and Applied Science University of Urbino Carlo Bo UrbinoI-61029 Italy Materials Science Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Physics & Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom CIFAR Azrieli Global Scholars Program 661 University Ave TorontoONM5G 1M1 Canada

Quantum sensors have notably advanced high-sensitivity magnetic field detection. Here, we report quantum sensors constructed from polarized spin-triplet electrons in photoexcited organic chromophores, specifically focusing on pentacene-doped para-terphenyl (≈0.1%). We demonstrate essential quantum sensing properties at room temperature (RT): optically-generated electronic polarization and state-dependent fluorescence contrast, by leveraging differential pumping and relaxation rates between triplet and ground states. We measure high optically-detected magnetic resonance (ODMR) contrast ≈16.8% of the triplet states at RT, along with long coherence times under spin echo and CPMG sequences, T2=2.7μs and T2DD=18.4μs, respectively, limited only by the triplet lifetimes. The material offers several advantages for quantum sensing, including the ability to grow large (cm-scale) crystals at low cost, absence of paramagnetic impurities, and electronic diamagnetism when not optically illuminated. Utilizing pentacene as a representative of a broader class of spin triplet- polarizable organic molecules, this study highlights new potential for quantum sensing in chemical systems. © 2024, CC BY.

关键词： Crystal impurities

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Giant Second-Order Nonlinearity and Anisotropy of Large-Sized Few-Layer SnS with Ferroelectric Stacking

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Advanced Optical materials 2024年第19期12卷

作者： Moqbel, Redhwan Nanae, Ryo Kitamura, Satsuki Lee, Ming-Hao Lan, Yann-Wen Lee, Chi-Cheng Nagashio, Kosuke Lin, Kung-Hsuan Department of Physics National Taiwan University No. 1 Sec. 4 Roosevelt Rd. Taipei106319 Taiwan Institute of Physics Academia Sinica No. 128 Sec. 2 Academia Rd. Nangang Dist. Taipei115201 Taiwan Nano-Science and Technology Program Taiwan International Graduate Program Academia Sinica No. 128 Sec. 2 Academia Rd. Nangang Dist. Taipei115201 Taiwan Department of Materials Engineering The University of Tokyo 7-3-1 Hongo Tokyo Bunkyo113-8656 Japan Center for Condensed Matter Sciences National Taiwan University Taipei10617 Taiwan The Key Consortium of Electron Microscopy National Taiwan University Taipei10617 Taiwan Department of Physics National Taiwan Normal University Taipei11677 Taiwan Department of Physics Tamkang University New Taipei Tamsui251301 Taiwan

The giant second-order nonlinearity of SnS with ferroelectric stacking is reported. Based on theoretical calculations, the susceptibility of second harmonic generation (SHG) from SnS with ferroelectric stacking is up to 1354 pm V−1, which is three orders of magnitude higher than the values of traditional nonlinear crystals such as BBO and KTP. The SHG from ferroelectric SnS few layers is experimentally measured and its intensity is found to be 131 times larger than that of a MoS2 monolayer under the same experimental conditions, with a photon energy of 1.55 eV. The SHG susceptibility is determined to be on the order of 100 pm V−1. Numerous SnS flakes are systematically investigated using polarization-resolved SHG. Micrometer-sized flakes with a single domain are found, and their SHG anisotropic patterns fit well with the theoretical calculations derived from first-principles methods. The variation in SHG anisotropic patterns, attributed to SHG interference from multiple domains, is investigated both theoretically and experimentally. Additionally, the impact of stacking disorder on the SHG anisotropic pattern is explored. It is demonstrated that polarization-resolved SHG microscopy is a valuable tool for identifying domains in SnS flakes and examining stacking disorder. © 2024 Wiley-VCH GmbH.

关键词： Harmonic generation

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Angle-resolved photoemission spectroscopy with an in situ tunable magnetic field

arXiv

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arXiv 2023年

作者： Huang, Jianwei Yue, Ziqin Baydin, Andrey Zhu, Hanyu Nojiri, Hiroyuki Kono, Junichiro He, Yu Yi, Ming Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Smalley–Curl Institute Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Institute for Materials Research Tohoku University Katahira 2-1-1 Sendai980-8577 Japan Department of Applied Physics Yale University New HavenCT06511 United States

Angle-resolved photoemission spectroscopy (ARPES) is a powerful tool for probing the momentum-resolved single-particle spectral function of materials. Historically, in situ magnetic fields have been carefully avoided as they are detrimental to the control of photoelectron trajectory during the photoelectron detection process. However, magnetic field is an important experimental knob for both probing and tuning symmetry-breaking phases and electronic topology in quantum materials. In this paper, we introduce an easily implementable method for realizing an in situ tunable magnetic field at the sample position in an ARPES experiment and analyze magnetic field induced artifacts in ARPES data. Specifically, we identified and quantified three distinct extrinsic effects of a magnetic field: Constant energy contour rotation, emission angle contraction, and momentum broadening. We examined these effects in three prototypical quantum materials, i.e., a topological insulator (Bi2Se3), an iron-based superconductor (LiFeAs), and a cuprate superconductor (Pb-Bi2Sr2CuO6+x), and demonstrate the feasibility of ARPES measurements in the presence of a controllable magnetic field. Our studies lay the foundation for the future development of the technique and interpretation of ARPES measurements of field-tunable quantum phases. Copyright © 2023, The Authors. All rights reserved.

关键词： Photoelectrons

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Spin-polarized phases of P23 superfluids in neutron stars

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Physical Review C 2021年第4期104卷 045803-045803页

作者： Takeshi Mizushima Shigehiro Yasui Daisuke Inotani Muneto Nitta Department of Materials Engineering Science Osaka University Toyonaka Osaka 560-8531 Japan Department of Physics and Research and Education Center for Natural Sciences Keio University Hiyoshi 4-1-1 Yokohama Kanagawa 223-8521 Japan Interdisciplinary Theoretical and Mathematical Sciences Program RIKEN Wako Saitama 351-0198 Japan

The interior of a neutron star is expected to be occupied by a neutron P23 superfluid, which is the condensate of spin-triplet p-wave Cooper pairs of neutrons with total angular momentum J=2. Here we investigate the thermodynamic stability of P23 superfluids in a neutron-star interior under a strong magnetic field. Using the theory incorporating the finite-size correction of the neutron Fermi surface, we show that the spin-polarized phases of P23 superfluids, the magnetized biaxial nematic phase, and the ferromagnetic phase appear in high temperatures and high magnetic fields. These phases were missed in the previous studies using the quasiclassical approximation in which dispersions of neutrons are linearized around the Fermi surface. In particular, the ferromagnetic phase, which is the condensation of Cooper-paired neutrons with fully polarized spins, appears between the normal phase and the biaxial nematic phase and enlarges the thermodynamic stability of P23 superfluids under strong magnetic fields. Furthermore, we present the augmented Ginzburg-Landau theory that incorporates the thermodynamic stability of spin-polarized P23 superfluid phases.

关键词： Nuclear matter in neutron stars Superfluidity

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Breaking Mechanical Holography in Combinatorial Metamaterials

arXiv

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arXiv 2024年

作者： Sirote-Katz, Chaviva Palti, Ofri Spiro, Naomi Kálmán, Tamás Shokef, Yair Department of Biomedical Engineering Tel Aviv University Tel Aviv69978 Israel The Future Scientists Center Alpha Program Tel Aviv Youth University Tel Aviv69978 Israel University of Illinois at Urbana-Champaign UrbanaIL61801 United States Department of Mathematics Institute of Science Tokyo H-214 2-12-1 Ookayama Tokyo Meguro-ku152-8551 Japan Hiroshima University Higashi-Hiroshima Hiroshima739-8526 Japan School of Mechanical Engineering Tel Aviv University Tel Aviv69978 Israel Center for Computational Molecular and Materials Science Tel Aviv University Tel Aviv69978 Israel Center for Physics and Chemistry of Living Systems Tel Aviv University Tel Aviv69978 Israel

Combinatorial mechanical metamaterials are made of anisotropic, flexible blocks, such that multiple metamaterials may be constructed using a single block type, and the system’s response strongly depends on the mutual orientations of the blocks within the lattice. We study a family of possible block types for the square, honeycomb, and cubic lattices. Blocks that are centrally symmetric induce holographic order, such that mechanical compatibility (meaning that blocks do not impede each other’s motion) implies bulk-boundary coupling. With them, one can design a compatible metamaterial that will deform in any desired texture only on part of its boundary. With blocks that break holographic order, we demonstrate how to design the deformation texture on the entire boundary. Correspondingly, the number of compatible holographic metamaterials scales exponentially with the boundary, while in non-holographic cases we show that it scales exponentially with the bulk. © 2024, CC BY.

关键词： Holography

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