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Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： Di Xing Cheng-Chieh Lin Ya-Lun Ho Yang-Chun Lee Mu-Hsin Chen Bo-Wei Lin Chun-Wei Chen Jean-Jacques Delaunay School of Engineering The University of Tokyo Tokyo Japan International Graduate Program of Molecular Science and Technology (NTU-MST) National Taiwan University and Academia Sinica Taipei Taiwan Department of Materials Science and Engineering National Taiwan University Taipei Taiwan Molecular Science and Technology Program Taiwan International Graduate Program (TIGP) Academia Sinica Taipei Taiwan Center of Atomic Initiative for New Materials (AI-MAT) National Taiwan University Taipei Taiwan

Metallic nanoparticles array is served as a promising way to realize on-chip lasers. To achieve high-performance lasers, efficient gain media are also critical. Here, we present a pressure-assisted process for CsPbBr3...

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A topological Hund nodal line antiferromagnet

arXiv

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arXiv 2024年

作者： Yang, Xian P. Yao, Yueh-Ting Zheng, Pengyu Guan, Shuyue Zhou, Huibin Cochran, Tyler A. Lin, Che-Min Yin, Jia-Xin Zhou, Xiaoting Cheng, Zi-Jia Li, Zhaohu Shi, Tong Hossain, Md Shafayat Chi, Shengwei Belopolski, Ilya Jiang, Yu-Xiao Litskevich, Maksim Xu, Gang Tian, Zhaoming Bansil, Arun Yin, Zhiping Jia, Shuang Chang, Tay-Rong Hasan, M. Zahid Department of Physics Princeton University PrincetonNJ United States Department of Physics National Cheng Kung University Tainan Taiwan School of Physics & Astronomy Center for Advanced Quantum Studies Beijing Normal University Beijing China International Center for Quantum Materials School of Physics Peking University Beijing China Department of Physics Southern University of Science and Technology Guangdong Shenzhen China Department of Physics Northeastern University BostonMA United States Quantum Materials and Sensing Institute Northeastern University BurlingtonMA United States School of Physics Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Hubei Wuhan China Institute for Quantum Science and Engineering Huazhong University of Science and Technology Hubei Wuhan China Wuhan Institute of Quantum Technology Hubei Wuhan China Beijing Normal University Beijing China Interdisciplinary Institute of Light-Element Quantum Materials Research Center for Light-Element Advanced Materials Peking University Beijing China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Beijing China Tainan Taiwan Physics Division National Center for Theoretical Sciences Taipei Taiwan Princeton Institute for Science and Technology of Materials Princeton University PrincetonNJ United States Lawrence Berkeley National Laboratory BerkeleyCA United States

The interplay of topology, magnetism, and correlations gives rise to intriguing phases of matter. In this study, through state-of-the-art angle-resolved photoemission spectroscopy, density functional theory and dynamical mean-field theory calculations, we visualize a fourfold degenerate Dirac nodal line at the boundary of the bulk Brillouin zone in the antiferromagnet YMn2Ge2. We further demonstrate that this gapless, antiferromagnetic Dirac nodal line is enforced by the combination of magnetism, space-time inversion symmetry and nonsymmorphic lattice symmetry. The corresponding drumhead surface states traverse the whole surface Brillouin zone. YMn2Ge2 thus serves as a platform to exhibit the interplay of multiple degenerate nodal physics and antiferromagnetism. Interestingly, the magnetic nodal line displays a d-orbital dependent renormalization along its trajectory in momentum space, thereby manifesting Hund’s coupling. Our findings offer insights into the effect of electronic correlations on magnetic Dirac nodal lines, leading to an antiferromagnetic Hund nodal line. © 2024, CC BY-NC-SA.

关键词： Antiferromagnetism

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Stable Cycling of Sodium All-Solid-State Batteries with High-Capacity Cathode Presodiation

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advanced Energy materials 2025年

作者： Tang, Wei Xu, Dapeng Wu, Junlin Lee, Dong Ju Fuqua, Alexander Li, Feng Jeon, Yuju Bian, Wenjuan Chen, Zheng Aiiso Yufeng Li Department of Chemical and Nano Engineering University of California La Jolla San DiegoCA92093 United States Program of Materials Science and Engineering University of California La Jolla San DiegoCA92093 United States Energy and Environment Science and Technology Idaho National Laboratory Idaho FallsID83415 United States Sustainable Power and Energy Center University of California La Jolla San DiegoCA92093 United States

Sodium all-solid-state batteries (NaSSBs) with an alloy-type anode (e.g., Sn and Sb) offer superior capacity and energy density compared to hard carbon anode. However, the irreversible loss of Na+ at the alloy anode during the initial cycle results in diminished capacity and stability, impairing full-cell performance. This study presents an easy-to-implement cathode presodiation strategy by employing a Na-rich material to address these challenges. Leveraging the high theoretical capacity and suitable voltage window, Na2S is chosen as the Na donor, which is activated by creating a mixed electron-ion conducting network, delivering a high capacity of 511.7 mAh g−1. By adding a small amount (i.e., 3 wt.%) of Na2S to the cathode composite, a NaCrO2 || Sn full cell demonstrated capacity improvement from 90.8 to 118.2 mAh g−1 (based on cathode mass). The capacity-balanced full cell can thus cycle to more than 300 times with >90% capacity retention. This work provides a practical solution to enhance the full-cell performance and advance the transformation from half-cell to full-cell applications of NaSSBs. © 2025 Wiley-VCH GmbH.

关键词： Solid-State Batteries

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Construction of Low Domain Wall Density in Pnn-Pin-Pt Piezoelectric Ceramics for High Electromechanical Performance Using Defect engineering

SSRN

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SSRN 2024年

作者： Liu, Jianning Fu, Zhe Yan, Yangxi Li, Zhimin Wang, Pangpang Murakami, Ri-Ichi Zhang, Dongyan Henan Polytechnic University China School of Advanced Materials and Nanotechnology Xidian University 266 Xinglong Section of Xifeng Road Xi’an710126 China Department of Electronic &Information Engineering School of Automatical Science and Engineering Xi’an Jiaotong University China 4-1 Kyudaishinmachi Nishi-ku Fukuoka819-0388 Japan School of Mechanical Engineering Chengdu University No. 2025 Chengluo Avenue Chengdu610106 China Shaanxi Key Laboratory of High-Orbits-Electron Materials and Protection Technology for Aerospace China

Good piezoelectric properties and low mechanical losses are prerequisites for the application of high-power devices. In this paper, by introducing an appropriate amount of Mn ions into a ceramic system with a high piezoelectric property of 0.46Pb(Ni1/3Nb2/3)O3-0.23Pb(In1/2Nb1/2)O3-0.31PbTiO3, the Qm of the ceramic system can be improved while maintaining high piezoelectric properties, and the dielectric loss can be reduced. d33 was reduced by only ~21%, while Qm was increased by ~13 times (d33=750 pC/N, Qm=385, tanδ= 0.66%). The measurement of the internal bias field Ei in the P-E curve of aged and nonaged samples verifies that the ageing process promotes the directional alignment of defect dipoles and improves their Qm. According to the PFM results, the significant increase in Qm is mainly due to the "bulk effect" caused by low domain wall density, and widening and lengthening of the domain promote the accumulation of most defective dipoles in the body, which greatly enhances the hardening effect. This work provides a good example of enhancing Qm in high d33 systems by constructing low domain wall densities to improve Qm. © 2024, The Authors. All rights reserved.

关键词： Piezoelectric ceramics

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Nitrogen Decoration of Basal Plane Dislocations in 4H-SiC

arXiv

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arXiv 2022年

作者： Li, Jiajun Luo, Hao Yang, Guang Zhang, Yiqiang Pi, Xiaodong Yang, Deren Wang, Rong State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Hangzhou310027 China Institute of Advanced Semiconductors Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices Hangzhou Innovation Center Zhejiang University Hangzhou311200 China Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of Physics Zhejiang Sci-Tech University Hangzhou310018 China School of Materials Science and Engineering Henan Institute of Advanced Technology Zhengzhou University Henan Zhengzhou450001 China

Basal-plane dislocations (BPDs) pose a great challenge to the reliability of bipolar power devices based on the 4H silicon carbide (4H-SiC). It is well established that heavy nitrogen (N) doping promotes the conversion of BPDs to threading edge dislocations (TEDs) and improves the reliability of 4H-SiC-based bipolar power devices. However, the interaction between N and BPDs, and the effect of N on the electronic properties of BPDs are still ambiguous, which significantly hinder the understanding on the electron-transport mechanism of 4H-SiC-based bipolar power devices. Combining molten-alkali etching and the Kelvin probe force microscopy (KPFM) analysis, we demonstrate that BPDs create acceptor-like states in undoped 4H-SiC, while acting as donors in N-doped 4H-SiC. First-principles calculations verify that BPDs create occupied defect states above the valence band maximum (VBM) and unoccupied defect states under the conduction-band minimum (CBM) of undoped 4H-SiC. The electron transfer from the defect states of intrinsic defects and native impurities to the unoccupied defect states of BPDs gives rise to the acceptor-like behavior of BPDs in undoped 4H-SiC. Defect formation energies indicate that N atoms can spontaneously decorate BPDs during the N doping of 4H-SiC. The binding between N and BPD is strong against decomposition. The accumulation of N dopants at the core of BPDs results in the accumulation of donor-like states at the core of BPDs in N-doped 4H-SiC. This work not only enriches the understanding on the electronic behavior of BPDs in N-doped 4H-SiC, but also helps understand the electron transport mechanism of 4H-SiC-based bipolar power devices. Copyright © 2022, The Authors. All rights reserved.

关键词： Doping (additives)

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Accelerating Wireless Federated Learning via Nesterov's Momentum and Distributed Principle Component Analysis

arXiv

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arXiv 2023年

作者： Dong, Yanjie Wang, Luya Chi, Yuanfang Wang, Jia Zhang, Haijun Yu, Fei Richard Leung, Victor C.M. Hu, Xiping The Faculty of Engineering Shenzhen MSU-BIT University Shenzhen China The College of Computer Science and Software Engineering Shenzhen University Shenzhen China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services Institute of Artificial Intelligence University of Science and Technology Beijing Beijing China The Department of Systems and Computer Engineering Carleton University Ottawa Canada The Department of Electrical and Computer Engineering The University of British Columbia Vancouver Canada

A wireless federated learning system is investigated by allowing a server and workers to exchange uncoded information via orthogonal wireless channels. Since the workers frequently upload local gradients to the server via bandwidth-limited channels, the uplink transmission from the workers to the server becomes a communication bottleneck. Therefore, a one-shot distributed principle component analysis (PCA) is leveraged to reduce the dimension of uploaded gradients such that the communication bottleneck is relieved. A PCA-based wireless federated learning (PCA-WFL) algorithm and its accelerated version (i.e., PCA-AWFL) are proposed based on the low-dimensional gradients and the Nesterov's momentum. For the non-convex loss functions, a finite-time analysis is performed to quantify the impacts of system hyper-parameters on the convergence of the PCA-WFL and PCA-AWFL algorithms. The PCA-AWFL algorithm is theoretically certified to converge faster than the PCA-WFL algorithm. Besides, the convergence rates of PCA-WFL and PCA-AWFL algorithms quantitatively reveal the linear speedup with respect to the number of workers over the vanilla gradient descent algorithm. Numerical results are used to demonstrate the improved convergence rates of the proposed PCA-WFL and PCA-AWFL algorithms over the benchmarks. © 2023, CC BY.

关键词： Momentum

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Multimodal Sensing Algorithm Using Thermoelectric Dynamics for Self-Powered Skin-Like Sensory Devices

SSRN

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SSRN 2023年

作者： Lee, Hyeju Baek, Jong Jin Oh, Jin Young Lee, Tae Il Department of Materials Science and Engineering Gachon University Gyeonggi Seong-Nam13120 Korea Republic of Advanced Development Team Ilji Tech Co. Ltd. Sinsang-ri Jillyang-eup Gyeongsangbuk-do Gyeongsan-si 12103 Korea Republic of Department of Chemical Engineering Integrated Engineering Program Kyung Hee University Yongin17104 Korea Republic of

In the rapidly evolving field of electronic skins (e-skins), the development of self-powered sensors has emerged as a promising solution to providing continuous and reliable power sources for embedded sensors. This study introduces a novel approach that incorporates spike-shaped nickel (Ni) microparticles into a styrene-ethylene-butylene-styrene (SEBS) matrix, resulting in a thermoelectric material that functions as both an energy harvester and a pressure sensor, and a multimodal sensing algorithm designed to mitigate pressure sensing errors arising from temperature fluctuations in the thermoelectric self-powered pressure sensor. The Ni-SEBS composite, with a sensing mechanism that identifies changes in the Ni particle percolation state induced by compressive strain, exhibited a high sensitivity of 0.6234 kPa-1. Based on this composite, a dual-channel self-powered sensor was fabricated using the proposed algorithm and attached to the skin;the sensor successfully detected various forms of external pressure applied to the skin without errors due to temperature changes. © 2023, The Authors. All rights reserved.

关键词： Pressure sensors

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Structural, dc electrical resistivity and magnetic investigation of Mg, Ni, and Zn substituted Co-Cu nano spinel ferrites

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South African Journal of Chemical engineering 2022年 42卷 106-114页

作者： Parajuli, D. Murali, N. Rao, A. Venkateswara Ramakrishna, A. S, Yonatan Mulushoa Samatha, K. Research Center for Applied Science and Technology Tribhuvan University KTM Nepal Department of Physics Tri-Chandra Multiple Campus KTM Ghantaghar Nepal Department of Engineering Physics AUCE (A) Andhra University A.P Visakhapatnam India Advanced Functional Materials Research Centre Department of Physics Koneru Lakshmaiah Education Foundation Andhra Pradesh Guntur 522502 India Department of ECE Aditya College of Engineering & Technology Surampalem Kakinada A. P. India Jawaharlal Nehru Technological University Kakinada East Godavari District A. P. India Department of Physics College of Natural and Computational Science Wolkite University Wolkite Ethiopia Department of Physics Andhra University A.P Visakhapatnam India

The sol-gel auto-combustion procedure was used to synthesize M (M = Mg, Ni, and Zn) substituted Co0.5Cu0.2M0.3Fe2O4 micro ferrites. X-ray diffraction measurements validated the mono-phase formation and nanocrystalline... 详细信息

The sol-gel auto-combustion procedure was used to synthesize M (M = Mg, Ni, and Zn) substituted Co_0.5Cu_0.2M_0.3Fe₂O₄ micro ferrites. X-ray diffraction measurements validated the mono-phase formation and nanocrystalline character of the produced samples. It possesses a monophasic cubic-spinel lattice structure with an average crystallite size ranging from 29.01 to 47.17 nm. The lattice constant determined by XRD analysis falls between 8.374 and 8.474 Å. The morphological characteristics were shown using FESEM analysis, which revealed the almost spherical form of grains with sizes ranging from 40, 50, and 74 nm. The compositional verification was undertaken with the help of the EDS analysis which ensured the presence of elements in desired proportions. IR spectra confirm their spinel spectra with the help of the two absorption bands lying between 1200 and 400 cm⁻¹ resembling their two sites: tetrahedral and octahedral. The magnetic saturation (M_S), magnetic moment (M)_R, and coercivity (H_c) are found to be the highest for the Ni substituted Co-Cu ferrite system, i.e., M_S = 49.5 emu/g. The ratio M_R/M_S for all ferrites is less than 0.5 indicating their ferromagnetic isotropic nature thereby acting as magnetic semiconductors. The electrical properties were measured using the ‘two probe technique’ with varying temperatures which indicates their semiconducting nature. Ni substituted Co-Cu nanoferrite is preferable for electromagnets and recording purposes the magnetic and electrical behavior of Ni substituted Co-Cu nanoferrite shows its relevance for recording and electromagnetic applications. © 2022 The Authors

关键词： Co-Cu ferrites DC resistivity FTIR Magnetic semiconductors XRD

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Effect of Substrate Roughness on Surface Morphology and Hydrogen Evolution Reaction of Ni-Co Alloys Films

SSRN

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SSRN 2024年

作者： Mohapatra, Lokanath Maurya, Abhinav Sonwane, Akshay Kumar Kumar, Ritunesh Kurzina, Irina A. Kushwaha, Ajay Kumar Department of Metallurgical Engineering and Materials Science Indian Institute of Technology Indore Simrol M.P. Indore453552 India Centre for Advanced Electronics Indian Institute of Technology Indore Simrol M.P. Indore453552 India Department of Mechanical Engineering Indian Institute of Technology Indore Simrol M.P. Indore453552 India Faculty of Chemistry National Research Tomsk State University Tomsk634050 Russia

Nanostructured Ni-Co alloys are electrodeposited on copper substrates with altered surface roughness. The etched copper substrate results in the deposition of Ni-Co micro-spheres. While nanosized, spherical particles of irregular shape are obtained in roughed and polished substrates. Structural analysis confirms the face-centered cubic (FCC) phase deposition of the Ni-Co alloy. Among the three samples, Ni-Co alloy deposited on an etched copper substrate shows the lowest overpotential of 221 mV vs. RHE for hydrogen evolution reaction. EIS measurement during the HER process revealed that Ni-Co alloy deposited on etched copper substrate exhibited a significantly lower resistance than smooth and rough surfaces. © 2024, The Authors. All rights reserved.

关键词： Electrodes

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Revealing the Charge Density Wave Caused by Peierls Instability in Two-Dimensional NbSe2

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ACS materials Letters 2024年第7期6卷 2941-2947页

作者： Lee, Yung-Ting Chen, Po-Tuan Li, Zheng-Hong Wu, Jyun-Yu Kuo, Chia-Nung Lue, Chin Shan Wu, Chien-Te Kuo, Chien-Cheng Chiang, Cheng-Tien Ozaki, Taisuke Lin, Chun-Liang Lee, Chi-Cheng Hsueh, Hung-Chung Chung, Ming-Chiang Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu300093 Taiwan Department of Vehicle Engineering National Taipei University of Technology Taipei10608 Taiwan Department of Physics National Cheng Kung University Tainan City70101 Taiwan Taiwan Consortium of Emergent Crystalline Materials National Science and Technology Council Taipei10601 Taiwan Physics Division National Center for Theoretical Sciences Taipei10617 Taiwan Department of Physics National Sun Yat-sen University Kaohsiung80424 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Department of Physics Tamkang University Tamsui New Taipei City251301 Taiwan Institute for Solid State Physics The University of Tokyo Kashiwa Chiba277-8581 Japan Center of Advanced Spectroscopy and Smart Inspection for Material Research Tamkang University Tamsui New Taipei City251301 Taiwan Department of Physics National Chung Hsing University Taichung40227 Taiwan Max Planck Institute for the Physics of Complex Systems Nöthnitzer Straße 38 Dresden01187 Germany

The formation of a charge density wave (CDW) in 2D materials caused by Peierls instability is a controversial topic. This study investigates the extensively debated role of Fermi surface nesting in causing the CDW state in 2H-NbSe2 materials. Four NbSe2 structures are identified on the basis of the characteristics in scanning tunneling microscopy images and first-principles simulations. The calculations reveal that an energetically favored filled phase corresponds to Peierls’ description with fully opened gaps at the CDW Brillouin zone boundary, resulting in a drop at the Fermi level in the density of states and scanning tunneling spectroscopy spectra. The electronic susceptibility and phonon instability indicate that the Fermi surface nesting is triggered by two nesting vectors, whereas the involvement of only one nesting vector leads to a so-called stripe phase. This comprehensive study demonstrates that the filled phase of NbSe2 can be categorized as a Peierls instability-induced CDW in two-dimensional systems. © 2024 American Chemical Society.

关键词： Charge density waves

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