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Magnetic and Electric Behavior of Spike- and Petal-Like Nanoscaled Cu:Zno Superstructures Diluted Magnetic Semiconductors

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SSRN 2022年

作者： Gunnewiek, Rodolfo Foster Klein Perdomo, Claudia P.F. Almeida, Diógenes F. Cancellieri, Igor C. Garcia, Leonardo A. Cardoso, André L.F. Federal University of São Carlos Graduate Program in Materials Science and Engineering Rod. Washington Luiz km 235 SP São Carlos13565-905 Brazil Federal University of Alfenas Graduate Program in Materials Science and Engineering Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400 Brazil Federal University of Alfenas Institute of Science and Technology Rod. José Aurélio Vilela BR 267 Km 533 11999 MG Poços de Caldas37715-400. Brazil

Room temperature ferromagnetism (RTFM) is the main condition for searching for materials to be applied in spintronics. Beyond the candidates, the diluted magnetic semiconductors (DMS) are potential materials for such application. The introduction of a foreign transition metal ion in the semiconductor lattice may lead to the RTFM, where the intrinsic ferromagnetism developed by a nonmagnetic ion is preferable for spintronics application. In this work, single-phase Cu-substituted zinc oxide was synthesized by a fast polymeric precursor method, providing nanocrystallites from 4 to 11 nm. Copper hindered grain growth, even for high Cu concentrations. The crystallites assembled to superstructures with petal and spike-like morphologies, following an unconventional crystallization. The texturization observed during the crystallization led to the development of unexpected weak RTFM. The number of oxygen vacancies is too small to promote the RTFM since few atoms of copper find attached to the vacancies. Probably the RTFM arises from overlapped spin-split bound magnetic polarons (BMP) due to the interaction of the hybridized O 2p and localized unoccupied twofold t2 subband of Cu 3d states. Although the sintering of pure and Cu-doped ZnO particles was equivalent, the electrical properties diverged. The copper insertion enhanced the resistivity and the non-linearity coefficient reached values higher than the unity. This is maybe due to the presence of copper at the grain boundaries forming a Schottky barrier. Neither the non-ohmic electrical behavior nor the RTFM from nanostructured superstructures was ever reported before. © 2022, The Authors. All rights reserved.

关键词： II-VI semiconductors

Design, Structure/Microstructure Evolution, Mechanical and Corrosion Properties of Two New Pseudo-High Entropy Amorphous Alloys

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SSRN 2023年

作者： Batalha, Weverson Capute Roche, Virginie Champion, Yannick Mantel, Marc Verdier, Marc Martin, Vincent Kiminami, Claudio S. Junior, Alberto M.J. Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS Grenoble INP LEPMI Grenoble38000 France Univ. Grenoble Alpes CNRS Grenoble INP SIMAP Grenoble38000 France Graduate Program of Materials Science and Engineering Federal University of São Carlos Dema São Carlos13565-905 Brazil

The influence of devitrification on structure/microstructure, corrosion, and mechanical properties of two new FeCrMoNbB and FeCrMoNiB pseudo-high entropy (PHE) amorphous alloys have been investigated to be used as coatings possibly. Specimens were characterized using several techniques. Amorphous ribbons produced by melt spinning were heat-treated to simulate crystallization, which may occur during coating processing. As PHE alloys, amounts of amorphous phases were kept at high temperatures and crystallized in multi-principal element (MPE) bcc or fcc phases, with few borides. A 500 μm thick physically simulated coatings of commercial-grade precursors using spray forming in the air were produced to infer their viability and glass-forming ability and confirm the crystallization path and mechanical properties. The coating of the Nb-PHE alloy was nearly amorphous, and the Ni-PHE one crystallized in phases of ribbons treated at 1000 °C with fewer borides. Nanoindentation evaluated the ribbons' mechanical behavior and coatings by Vickers microhardness. Ribbons' hardness and elastic modulus depended on annealing temperatures and were very high, indicating high wear resistance. Hardness values were confirmed by the simulated coatings. Corrosion properties evaluated by potentiodynamic polarization in seawater at different pHs showed outstanding corrosion resistance in amorphous conditions. After devitrification, both compositions preserved excellent corrosion behavior up to ~700 °C. However, the Nb-PHE alloy corrosion resistance was better than the Ni-PHE alloy. Pitting corrosion was not present in any condition. Even after crystallization, resistance to corrosion and wear indicates that these materials are promising for coating applications through different techniques. © 2023, The Authors. All rights reserved.

关键词： Entropy

Direct Visualization of a Disorder Driven Electronic Smectic Phase in Dirac Nodal Line Semimetal GdSbTe

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arXiv

arXiv 2024年

作者： Venkatesan, Balaji Guan, Syu-You Chang, Jen-Te Chiu, Shiang-Bin Yang, Po-Yuan Su, Chih-Chuan Chang, Tay-Rong Raju, Kalaivanan Sankar, Raman Fongchaiya, Somboon Chu, Ming-Wen Chang, Chia-Seng Chang, Guoqing Lin, Hsin Del Maestro, Adrian Kao, Ying-Jer Chuang, Tien-Ming Department of Physics National Taiwan University Taipei10617 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica National Taiwan University Taipei11529 Taiwan Institute of Physics Academia Sinica Taipei11529 Taiwan Department of Physics National Cheng-Kung University Tainan701 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei10617 Taiwan Molecular Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link 637371 Singapore Department of Physics and Astronomy University of Tennessee KnoxvilleTN37996 United States Institute for Advanced Materials & Manufacturing University of Tennessee KnoxvilleTN37996 United States Min H. Kao Department of Electrical Engineering and Computer Science University of Tennessee KnoxvilleTN37996 United States Center for Quantum Science and Technology National Taiwan University Taipei10607 Taiwan

Electronic liquid crystal (ELC) phases are spontaneous symmetry breaking states believed to arise from strong electron correlation in quantum materials such as cuprates and iron pnictides. Here, we report a direct observation of a smectic phase in a weakly correlated Dirac nodal line (DNL) semimetal GdSbxTe2-x. Incommensurate smectic charge modulation and intense local unidirectional nanostructure are visualized by using spectroscopic imaging - scanning tunneling microscopy. As topological materials with symmetry protected Dirac or Weyl fermions are mostly weakly correlated, the discovery of such an ELC phase are anomalous and raise questions on the origin of their emergence. Specifically, we demonstrate how chemical substitution generates these symmetry breaking phases before the system undergoes a charge density wave (CDW) - orthorhombic structural transition. Our results highlight the importance of impurities in realizing ELC phases and present a new material platform for exploring the interplay among quenched disorder, topology and electron correlation. Copyright © 2024, The Authors. All rights reserved.

关键词： Charge density waves

Addressing challenges for operating electrochemical solar fuels technologies under variable and diurnal conditions

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Frontiers in Energy Research 2024年 12卷

作者： Yap, Kyra M. K. Lee, Sol A. Kistler, Tobias A. Collins, Darci K. Warren, Emily L. Atwater, Harry A. Jaramillo, Thomas F. Xiang, Chengxiang Nielander, Adam C. Department of Chemical Engineering Stanford University StanfordCA United States SUNCAT Center for Interface Science and Catalysis SLAC National Accelerator Laboratory Menlo ParkCA United States Department of Applied Physics and Materials Science California Institute of Technology PasadenaCA United States Chemical Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA United States Chemistry and Nanoscience Center National Renewable Energy Laboratory GoldenCO United States Advanced Energy Systems Graduate Program Colorado School of Mines GoldenCO United States

The outdoor operation of electrochemical solar fuels devices must contend with challenges presented by the cycles of solar irradiance, temperature, and other meteorological factors. Herein, we discuss challenges associated with these fluctuations presented over three timescales, including the effects of diurnal cycling over the course of many days, a single diurnal cycle over the course of hours, and meteorological phenomena that cause fluctuations on the order of seconds to minutes. We also highlight both reaction-independent and reaction-specific effects of variable conditions for the hydrogen evolution reaction and CO2 reduction reaction. We identify key areas of research for advancing the outdoor operation of solar fuels technology and highlight the need for metrics and benchmarks to enable the comparison of diurnal studies across systems and geographical locations. Copyright © 2024 Yap, Lee, Kistler, Collins, Warren, Atwater, Jaramillo, Xiang and Nielander.

关键词： Hydrogen fuels

Mechanically reprogrammable Pancharatnam-Berry metasurface for microwaves

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Advanced Photonics 2022年第1期4卷 69-79页

作者： Quan Xu Xiaoqiang Su Xueqian Zhang Lijuan Dong Lifeng Liu Yunlong Shi Qiu Wang Ming Kang Andrea Alù Shuang Zhang Jiaguang Han Weili Zhang Tianjin University Center for Terahertz Waves and College of Precision Instrument and Optoelectronics EngineeringKey Laboratory of Optoelectronic Information Technology(Ministry of Education of China)TianjinChina Shanxi Datong University Institute of Solid State Physics and College of Physics and Electronic ScienceShanxi Province Key Laboratory of Microstructure Electromagnetic Functional MaterialsDatongChina Wuhan University of Technology School of Information EngineeringWuhanChina Tianjin Normal University College of Physics and Materials ScienceTianjinChina City University of New York Advanced Science Research CenterPhotonics InitiativeNew YorkUnited States City University of New York Graduate CenterPhysics ProgramNew YorkUnited States University of Hong Kong Faculty of ScienceDepartment of PhysicsHong KongChina University of Hong Kong Department of Electrical and Electronic EngineeringHong KongChina Guilin University of Electronic Technology Guangxi Key Laboratory of Optoelectronic Information ProcessingSchool of Optoelectronic EngineeringGuilinChina Oklahoma State University School of Electrical and Computer EngineeringStillwaterOklahomaUnited States

Metasurfaces have enabled the realization of several optical functionalities over an ultrathin platform,fostering the exciting field of flat *** metasurfaces are achieved by arranging a layout of static meta-atoms to imprint a desired operation on the impinging wavefront,but their functionality cannot be *** and programmability of metasurfaces are the next important step to broaden their impact,adding customized on-demand functionality in which each meta-atom can be individually *** demonstrate a mechanical metasurface platform with controllable rotation at the meta-atom level,which can implement continuous Pancharatnam–Berry phase control of circularly polarized *** the proof-of-concept experiments,we demonstrate metalensing,focused vortex beam generation,and holographic imaging in the same metasurface template,exhibiting versatility and superior *** dynamic control of electromagnetic waves using a single,low-cost metasurface paves an avenue towards practical applications,driving the field of reprogrammable intelligent metasurfaces for a variety of applications.

关键词： reprogrammable metasurfaces Pancharatnam-Berry phase mechanical metasurfaces microwaves

Electrospun Nanofibers from Poly (Ε-Caprolactone) with Copaiba (Copaifera Sp)Oleoresin as an Advanced Healer

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SSRN 2024年

作者： Marcos Pinho da Silva, Andrey Miotto, Marília Afonso Provenzi, Marcel Lopes, Susane Maraschin, Marcelo Merlini, Claudia Sciences and Materials Engineering Graduate Program Federal University of Santa Catarina Reitor João David Ferreira Lima University Campus SC Florianópolis88040-900 Brazil Department of Materials Engineering Technology College Federal University of Amazonas AM Manaus Brazil Food Microbiology Laboratory Departament of Food Science and Technology Federal University of Santa Catarina Agrarian Sciences Center Av. Admar Gonzaga 1346 - Itacorubi SC . Florianópolis88034-001 Brazil Florianópolis Brazil Rua João Pessoa 2750 Bairro Velha Blumenau SC 89036-256 Brazil

Advanced healing developed using electrospinning show advantages such as highsurface area/volume relation, similarity with the skin extracellular matrix and ability toincorporate bioactive agents. The use of natural compounds, as the copaiba oleoresinresults in benefits due to its action as enhancer of biochemical agents during theinflammatory phase in the healing process. This study investigated the development ofnanofiber from polycaprolactone and copaiba oleoresin aiming at demonstrating itsantimicrobial and atoxic properties with healing effect on complex wounds. Thecopaiba oleoresin chemical composition revealed the predominance of sesquiterpenes,with majoritary components such as Caryophyllane, γ-Muurolene, and α-Copaene. Thenanofibers were anlyzed employing several techniques and revealed suitablephysicochemical characteristics for the development of advanced healing. The zetapotential indicated a negative surface load in the nanofibers, suggesting favorableinteractions for biomedical applications such as cell adherence. The copaiba oleoresinpresence significantly increased the liquid absorption ability, fundamental in advancedhealing, and accelerated the mass loss rate, emphasizing its influence in thebiodegradability of the nanofibers. The nanofibers showed efficacy againstStaphylococcus Aureus, while the cell viability assay indicared absence of *** results suggest the potential of these nanofibers as efficient and sustainableantimicrobial healing for clinical applications © 2024, The Authors. All rights reserved.

关键词： Nanofibers

Million-Q Free Space Meta-Optical Resonator at Visible Wavelengths

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arXiv

arXiv 2024年

作者： Fang, Jie Chen, Rui Sharp, David Renzi, Enrico M. Manna, Arnab Kala, Abhinav Mann, Sander A. Yao, Kan Munley, Christopher Rarick, Hannah Tang, Andrew Pumulo, Sinabu Zheng, Yuebing Menon, Vinod M. Alù, Andrea Majumdar, Arka Department of Electrical and Computer Engineering University of Washington SeattleWA98195 United States Department of Physics University of Washington SeattleWA98195 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Physics Program Graduate Center City University of New York New YorkNY10016 United States Walker Department of Mechanical Engineering Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Department of Physics City College of New York New YorkNY10031 United States

High-quality (Q)-factor optical resonators with extreme temporal coherence are of both technological and fundamental importance in optical metrology1,2, continuous-wave lasing3-5, and semiconductor quantum optics6-8. Despite extensive efforts in designing high-Q resonators across different spectral regimes, the experimental realization of very large Q-factors at visible wavelengths remains challenging due to the small feature size that is sensitive to fabrication imperfections9-12, and thus is typically implemented in integrated photonics1-4,9,10. In the pursuit of free-space optics with the benefits of large space-bandwidth product and massive parallel operations13,14, here we design and fabricate a visible-wavelength etch-free metasurface with minimized fabrication defects and experimentally demonstrate a million-scale ultrahigh-Q resonance. A new laser-scanning momentum-space-resolved spectroscopy technique with extremely high spectral and angular resolution is developed to characterize the record-high Qfactor as well as the dispersion of the million-Q resonance in free space. By integrating monolayer WSe2 into our ultrahigh-Q meta-resonator, we further demonstrate laser-like highly unidirectional and narrow-linewidth exciton emission, albeit without any operating power density threshold. Under continuous-wave laser pumping, we observe pump-power-dependent linewidth narrowing at room temperature, indicating the potential of our meta-optics platform in controlling coherent quantum light-sources. Our result also holds great promise for applications like optical sensing, spectral filtering, and few-photon nonlinear optics. Copyright © 2024, The Authors. All rights reserved.

关键词： Continuous wave lasers

Low-Temperature Synthesis of Weakly Confined Carbyne inside Single-Walled Carbon Nanotubes

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arXiv

arXiv 2024年

作者： Zhang, Bo-Wen Qiu, Xi-Yang Ma, Yicheng Hu, Qingmei Fitó-Parera, Aina Kohata, Ikuma Feng, Ya Zheng, Yongjia Zhang, Chiyu Matsuo, Yutaka Wang, YuHuang Chiashi, Shohei Otsuka, Keigo Xiang, Rong Levshov, Dmitry I. Cambré, Sofie Wenseleers, Wim Rotkin, Slava V. Maruyama, Shigeo Department of Mechanical Engineering The University of Tokyo Tokyo113-8656 Japan State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou310027 China Theory and Spectroscopy of Molecules and Materials Department of Physics University of Antwerp Antwerp2610 Belgium Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power Engineering Dalian University of Technology Liaoning 116024 China Department of Chemistry and Biochemistry Chemical Physics Program Maryland Nano Center University of Maryland College ParkMD20742 United States Department of Chemical Systems Engineering Graduate School of Engineering Nagoya University Nagoya464-8603 Japan Institute of Materials Innovation Institutes for Future Society Nagoya University Nagoya464-8603 Japan Theory and Spectroscopy of Molecules and Materials Department of Chemistry University of Antwerp Antwerp2610 Belgium Nanostructured and Organic Optical and Electronic Materials Department of Physics University of Antwerp Antwerp2610 Belgium Materials Research Institute Department of Engineering Science & Mechanics The Pennsylvania State University University ParkPA16802 United States

Carbyne, a one-dimensional (1D) carbon allotrope with alternating triple and single bonds, has the highest known mechanical strength but is unstable to bending, limiting synthesis to short linear chains. Encapsulation within carbon nanotubes (CNTs) stabilizes carbyne, forming confined carbyne (CC), thus enabling further research concerning attractive 1D physics and materials properties of carbyne. While CC has been synthesized in multi-walled CNTs (MWCNTs) using the arc-discharge method and in double-walled CNTs (DWCNTs) via high-temperature high-vacuum (HTHV) method, synthesis in single-walled CNTs (SWCNTs) has been challenging due to their fragility under such conditions. In this work, we report a low-temperature method to synthesize CC inside SWCNTs (CC@SWCNT). By annealing SWCNTs containing ammonium deoxycholate (ADC) at 400°C, ADC is converted into CC without damaging the SWCNTs. Raman spectroscopy revealed a strong CC phonon (CC-mode) peak at 1860–1870 cm-1, much stronger than the SWCNT G-band peak, confirming a high fraction of CC in the resulting material. The Raman mapping result showed the uniformity of the CC-mode signal across the entire film sample, proving the high efficiency of this method in synthesizing CC in every SWCNT of appropriate size. Notably, the CC-mode peaks of CC@SWCNT (above 1860 cm-1) are higher than those reported in previous CC@CNT samples (mostly -1). This is attributed to larger SWCNT diameters (>0.95 nm) used in this study, compared to the typical 0.6–0.8 nm range. Larger diameters result in reduced confinement, allowing carbyne to closely resemble free-standing carbyne while remaining stabilized. This low-temperature synthesis of long-chain, nearly freestanding carbyne within large-diameter SWCNTs offers new opportunities for exploring 1D physics and the unique properties of carbyne for potential applications. © 2024, CC BY-NC-ND.

关键词： Single-walled carbon nanotubes (SWCN)

Unleashing the Power of Nature: Eco-Friendly Mussel-Byssus-Inspired Pbs/Pbat Fishing Gear for Biodegradation by Marine Microbes

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SSRN 2023年

作者： Hong, Yuri Yang, Ho-Sung Lee, Min Hee Kim, Sinyang Park, Sung Bae Hwang, Sung Yeon Park, Jeyoung Koo, Jun Mo Oh, Dongyeop Hwang, Dong Soo Gyeongsangbuk-do Pohang37673 Korea Republic of Ulsan44429 Korea Republic of Department of Plant & Environmental New Resources Graduate School of Biotechnology Kyung Hee University Gyeonggi-do 17104 Korea Republic of Department of Chemical and Biomolecular Engineering Sogang University Seoul04107 Korea Republic of Department of Organic Materials Engineering Chungnam National University Daejeon34134 Korea Republic of Department of Polymer Science and Engineering and Program in Environmental and Polymer Engineering Inha University Incheon22212 Korea Republic of

Abstract Abandoned, lost, and discarded fishing gear (ALDFG) poses global challenges for marine ecosystems as they destroy algal forests, the largest oceanic carbon dioxide sinks. Biodegradable polybutylene succinate (PBS), which has a tensile toughness similar to that of nylon, has been suggested as a potential fishing-gear material. However, its slow degradation in the marine environment and limited draping characteristics need to be addressed before it can be used in environmentally friendly fishing gear. Inspired by the mussel byssus, a mussel-thread-like holdfast known for its stiff yet extensible mechanical properties, we developed fishing gear using a mussel-byssus-mimetic fiber (artificial byssus, AB) structure. The AB was composed of poly(butylene adipate-co-butylene terephthalate) (PBAT) fibers with favorable draping characteristics coated with mechanically resilient and PBS, which demonstrated sufficient toughness and draping properties for use in fishing gear. The AB may serve as fishing-gear material capable of mitigating ALDFG issues, given its marine degradability by microbial strains that degrade PBS and PBAT. Furthermore, it could serve as a substrate for ocean afforestation, given the improved settlement and growth of seaweed spores (Pyropia yezoensis) on AB. Overall, AB-based fishing gear is expected to enhance macroalgal forest conservation and expansion, and facilitate marine carbon capture through marine afforestation. © 2023, The Authors. All rights reserved.

关键词： Butenes