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SSRN 2024年

作者： Zhai, Xuedong Heye-Smith, Karina Mao, Xiaoming Arruda, Ellen M. Department of Mechanical Engineering University of Michigan Ann ArborMI United States Department of Physics University of Michigan Ann ArborMI United States Department of Biomedical Engineering University of Michigan Ann ArborMI United States Program in Macromolecular Science and Engineering University of Michigan Ann ArborMI United States

It is well known that armor prevents failures of behind-armor targets by reducing the force in an impact event and thereby providing protection under certain impact events. However, the kinetic energy associated with an impact, often underappreciated in impact events, can be as fatal as the force by causing relative motion in the target and destructive damage as a consequence. Therefore, efficient protection gear and packaging should be lightweight and good at force reduction as well as energy mitigation. Although auxetic lattices have been studied as lightweight alternatives for force reduction, simultaneous optimization of force reduction and energy dissipation in impact mitigation via geometric and material choices for auxetic lattices has not been addressed. In the present study, we show that a 2D auxetic lattice with an optimized slenderness ratio of the struts that comprise the lattice and optimized elastic and visco-elastic material properties can not only reduce the transmitted peak force but also mitigate the energy significantly. A multi-step optimization method using Finite Element (FE) analysis and a verification procedure via impact experiments are described by which an optimal design of the auxetic lattice can be achieved by simultaneously considering both peak force and energy mitigation. © 2024, The Authors. All rights reserved.

关键词： Armor

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基于合成磁场的声学非互易

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Science Bulletin 2023年第19期68卷 2164-2169,M0003页

作者：陈召宪李正伟翁经锴梁彬陆延青程建春 Andrea Alù Collaborative Innovation Center of Advanced Microstructures Key Laboratory of Modern Acoustics of Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China College of Engineering and Applied Sciences Nanjing UniversityNanjing 210093China Photonics Initiative Advanced Science Research CenterCity University of New YorkNew York NY 10031USA Physics Program Graduate CenterCity University of New YorkNew York NY 10016USA

通过设计特定的时空调制,合成磁性的概念最近被提出以实现对光子和声子等电荷中性粒子的非互易操控,但现有方案存在着隔离度低、信号频率变化等问题.本文设计了一种新型耦合共振腔系统,其中动态耦合的相位作为实现声学合成磁场的新机制... 详细信息

通过设计特定的时空调制,合成磁性的概念最近被提出以实现对光子和声子等电荷中性粒子的非互易操控,但现有方案存在着隔离度低、信号频率变化等问题.本文设计了一种新型耦合共振腔系统,其中动态耦合的相位作为实现声学合成磁场的新机制并打破了系统的时间反演对称性,最终取得了优异的声波非互易传输.基于旋转波近似方法,作者严格推导出了实现系统强非互易声传输的参数条件.通过优化动态耦合之间的相位差以及耦合强度,实验展示了隔离度达45-dB和正向传输率达0.85的优异单向声传输.此外,这种单向声传输具有始末态频率不变和隔离方向可电控等重要特性.该研究突破了现有声波单向操控机制在效率和隔离度方面的局限,并为实现弗洛奎和非线性声学拓扑绝缘体提供了新途径.

关键词：隔离度信号频率动态耦合非线性声学拓扑绝缘体耦合共振耦合强度声传输

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Improved Band Gaps and Structural Properties from Wannier-Fermi-Löwdin Self-Interaction Corrections for Periodic Systems

arXiv

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arXiv 2022年

作者： Shinde, Ravindra Yamijala, Sharma S.R.K.C. Wong, Bryan M. Department of Chemical & Environmental Engineering Materials Science & Engineering Program Department of Chemistry Department of Physics & Astronomy University of California-Riverside RiversideCA United States

The accurate prediction of band gaps and structural properties in periodic systems continues to be one of the central goals of electronic structure theory. However, band gaps obtained from popular exchange-correlation functionals (such as LDA and PBE) are severely underestimated partly due to the spurious self-interaction error (SIE) inherent to these functionals. In this work, we present a new formulation and implementation of Wannier function-derived Fermi-Löwdin (WFL) orbitals for correcting the SIE in periodic systems. Since our approach utilizes a variational minimization of the self-interaction energy with respect to the Wannier charge centers, it is computationally more efficient than the HSE hybrid functional and other self-interaction corrections that require a large number of transformation matrix elements. Calculations on several (17 in total) prototypical molecular solids, semiconductors, and wide-bandgap materials show that our WFL self-interaction correction approach gives better band gaps and bulk moduli compared to semilocal functionals, largely due to the partial removal of self-interaction errors. © 2022, CC BY.

关键词： Energy gap

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Structural, magnetic, and electronic properties of a GdAsSe single crystal: Experimental and theoretical studies

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Physical Review B 2024年第18期109卷 184420-184420页

作者： R. Kalaivanan Balaji Venkatesan B. Dundi Sri Chandana Rajesh Kumar Ulaganathan G. Senthil Murugan K. Moovendaran Joydev Khatua Li-Hsin Su W. Zhou Xiaofeng Xu Chia-Seng Chang Tien-Ming Chuang Yoshiyuki Iizuka I. Panneer Muthuselvam Horng-Tay Jeng Kwang-Yong Choi Raman Sankar Institute of Physics Academia Sinica Taipei 10617 Taiwan Department of Physics National Taiwan University Taipei 10617 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica and National Taiwan University Taipei 11529 Taiwan Department of Physics School of Basic and Applied Sciences Central University of Tamil Nadu Neelakudi Thiruvarur 610005 Tamil Nadu India Department of Physics Sungkyunkwan University Suwon 16419 Republic of Korea Department of Physics National Tsing Hua University Hsinchu 30013 Taiwan Department of Electro Physics National Yang Ming Chiao Tung University Hsinchu 300093 Taiwan School of Electronic and Information Engineering Changshu Institute of Technology Changshu 215500 China Department of Applied Physics Zhejiang University of Technology Hangzhou 310023 China Institute of Earth Sciences Academia Sinica Taipei 10617 Taiwan Department of Physics (MMV) Banaras Hindu University Varanasi 221005 Uttar Pradesh India Physics Division National Center for Theoretical Sciences Taipei 10617 Taiwan

We report high-quality single-crystal growth, x-ray diffraction, magnetic susceptibility [χ(T,H)], magnetization [M(H)], heat capacity [CP(T,H)], electrical resistivity [ρ(T,H)], and electron spin resonance (ESR) measurements of GdAsSe as functions of temperature and magnetic field. We identify an antiferromagnetic phase transition at TN∼11.9±0.2 K and construct magnetic phase diagrams for H||ab and H||c axes based on the χ(T,H) and CP(T,H) data. Isothermal M(H) curves along the H||ab direction at 3 K exhibit a field-induced spin orientation at HC∼3.78T. Both M(H) and χ(T,H) indicate an easy-plane-type anisotropy. The Curie-Weiss analysis of the high-temperature paramagnetic χ(T) yields a negative Weiss temperature, suggesting dominant antiferromagnetic interactions between the Gd ions. Magnetic entropy reaches 83% of R ln8 at TN. The presence of residual entropy above TN and the persistence of ESR critical broadening up to ∼3TN alludes to a degree of magnetic frustration in the studied material. The ρ(T) data above TN is well fitted to the Bloch-Grüneisen theory for metals. Further, density functional theory calculations reveal an antiferromagnetic ground state where the Gd atoms are coupled ferromagnetically in the ab plane and antiferromagnetically along the c axis.

关键词： Magnetic anisotropy Magnetic coupling Magnetic interactions Magnetic order Magnetism

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Electronic and Structural Insights into Boron Nitride Counterparts of Net-(Y,W)

SSRN

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SSRN 2024年

作者： Lima, Kleuton Antunes Lopes dos Santos, Emanuel José Alexandrino de Mendonça, Fábio Lúcio Lopes da Silva, Daniel Alves Giozza, William Ferreira Ribeiro, Luiz Antonio Institute of Physics University of Brasília Brasília70910-900 Brazil Computational Materials Laboratory LCCMat Institute of Physics University of Brasília Brasília70910-900 Brazil Department of Electrical Engineering Faculty of Technology University of Brasília Brasília Brazil Professional Postgraduate Program in Electrical Engineering - PPEE University of Brasília Brasília Brazil

Computational materials play a crucial role in comprehending various material classes and their properties, offering valuable insights for predicting novel structures and complementing experimental approaches. Net-(C,Y,W) has emerged as stable two-dimensional carbon allotropes of 4-6-8 carbon rings within this framework. This study uses density functional theory calculations and ab initio molecular dynamics simulations to explore the structural, electronic, optical, and mechanical properties of their boron nitride counterparts, named NetBN-W and NetBN-Y, with NetBN-C already investigated. The electronic analysis reveals an insulating characteristic for NetBN-W and a potential wide band gap semiconducting nature for NetBN-Y, with values of 5.12 eV and 3.71 eV, respectively. Optical properties examination indicates UV activity for these materials, accompanied by optical anisotropy between the x and y directions. Evaluation of mechanical properties also uncovers significant anisotropy in both materials, with Young's moduli reaching 417.58 GPa for NetBN-W and 433.31 GPa for NetBN-Y when stretched in the y-direction of the basal plane. The nearly zero Young's modulus for NetBN-Y in the x-direction signifies its substantial instability under tension due to nitrogen bonds parallel to the strain direction. These findings offer valuable insights into the fundamental properties of NetBN-W and NetBN-Y and their potential applications. © 2024, The Authors. All rights reserved.

关键词： Density functional theory

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Braiding fractional quantum Hall quasiholes on a superconducting quantum processor

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Physical Review B 2023年第6期108卷 064303-064303页

作者： Ammar Kirmani Derek S. Wang Pouyan Ghaemi Armin Rahmani Physics Department City College of the City University of New York New York 10031 USA IBM Quantum IBM T.J. Watson Research Center Yorktown Heights 10598 USA Physics Program Graduate Center of City University of New York New York 10031 USA Department of Physics and Astronomy and Advanced Materials Science and Engineering Center Western Washington University Bellingham Washington 98225 USA

Direct experimental detection of anyonic exchange statistics in fractional quantum Hall systems by braiding the excitations and measuring the wave-function phase is an enormous challenge. Here, we use a small, noisy quantum computer to emulate direct braiding within the framework of a simplified model applicable to a thin cylinder geometry and measure the topological phase. Our algorithm first prepares the ground state with two quasiholes. It then applies a unitary operation controlled by an ancilla, corresponding to a sequence of adiabatic evolutions that take one quasihole around the other. We finally extract the phase of the wave function from measuring the ancilla with a compound error mitigation strategy. Our results point out an avenue for studying braiding statistics in fractional Hall states.

关键词： Anyons Fractional quantum Hall effect Quantum algorithms Superconducting devices

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Increased light-emission efficiency in disordered InGaN through the correlated reduction of recombination rates

arXiv

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arXiv 2023年

作者： Pant, Nick Kioupakis, Emmanouil Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States

Experiments have shown that the light-emission efficiency of indium gallium nitride (InGaN) light-emitting diodes improves with increasing indium concentration. It is widely thought that compositional fluctuations due to indium incorporation suppress diffusion of carriers to non-radiative centers, thus leading to defect-insensitive emission. However, recent experiments have challenged this hypothesis by revealing unexpectedly long diffusion lengths at room temperature. Here, we demonstrate an alternative mechanism involving the correlated reduction in radiative and nonradiative recombination rates that explains the increase in light-emission efficiency of InGaN with increasing indium concentration, without invoking the suppression of carrier diffusion. Our analysis challenges the notion that carrier localization gives rise to defect tolerance in InGaN. Copyright © 2023, The Authors. All rights reserved.

关键词： III-V semiconductors

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A Comprehensive Study on How Different Mineralization Processes Affect Native Structure of Wetspun Collagen Fibers and Mineral Quality by Using S(Ftir)

SSRN

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SSRN 2024年

作者： Hacıosmanoğlu, Selçuk Kaan Belet, Abdulbaki Kamel, Gihan Kazanci, Murat Nanoscience and Nanoengineering Program Graduate School Istanbul Medeniyet University Istanbul34700 Turkey Biomedical Engineering Department School of Engineering and Natural Sciences Istanbul Medeniyet University Istanbul34700 Turkey Allan19252 Jordan Department of Physics Faculty of Sciences Helwan University Cairo Egypt

The collagen fibers could easily be produced via wet-spinning and mineralized by employing different mineralization methods. Herein, three different methods are used to obtain mineralized collagen fibers those are the Polymer-Induced Liquid-Precursor (P.I.L.P.), In-situ and Hydroxyapatite Mineral Addition (H.A.M.A.). Synchrotron Fourier-Transform Infrared Microspectroscopy is a powerful tool that sheds light on the molecular structure of collagen fibers. In this paper we discussed three different mineralization methods and detail their effects on the structure of collagen. One of the discussed highlights is that the applied mineralization methods caused distinct spectral shifts for the protein bands’ positions. It is demonstrated that among the suggested mineralization methods, In-situ and PILP have less, and H.A.M.A. has more effect on the native structure of collagen bundles and PILP gives the higher ratio of Ca/PO4. © 2024, The Authors. All rights reserved.

关键词： Collagen

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Large effective magnetic fields from chiral phonons in rare-earth halides

arXiv

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arXiv 2023年

作者： Luo, Jiaming Lin, Tong Zhang, Junjie Chen, Xiaotong Blackert, Elizabeth R. Xu, Rui Yakobson, Boris I. Zhu, Hanyu Department of Materials Science and Nano Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Rice University HoustonTX77005 United States

Time-reversal symmetry (TRS) is pivotal for materials’ optical, magnetic, topological, and transport properties. Chiral phonons, characterized by atoms rotating unidirectionally around their equilibrium positions, generate dynamic lattice structures that break TRS. Here we report that coherent chiral phonons, driven by circularly polarized terahertz light pulses, can polarize the paramagnetic spins in CeF3 like a quasi-static magnetic field on the order of 1 Tesla. Through time-resolved Faraday rotation and Kerr ellipticity, we found the transient magnetization is only excited by pulses resonant with phonons, proportional to the angular momentum of the phonons, and growing with magnetic susceptibility at cryogenic temperatures, as expected from the spin-phonon coupling model. The time-dependent effective magnetic field quantitatively agrees with that calculated from phonon dynamics. Our results may open a new route to directly investigate mode-specific spin-phonon interaction in ultrafast magnetism, energy-efficient spintronics, and non-equilibrium phases of matter with broken TRS. Copyright © 2023, The Authors. All rights reserved.

关键词： Phonons

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Preparation of graphitic carbon nitride (g-C3N4) for novel dielectric and photocatalytic dye removal applications

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Physica Scripta 2023年第9期98卷 095904-095904页

作者： Gupta, Aayush Jaidka, Sachin Rajagopalan, Pandey Mehtani, Hitesh Kumar Singhal, Varun Pandey, O.P. Department of Mechanical Engineering GLA University Uttar Pradesh Mathura281406 India School of Physics and Materials Science Thapar Institute of Engineering and Technology Punjab Patiala147004 India Cross College of Elite Program National Cheng Kung University Tainan70101 Taiwan Mechanical Engineering Department Thapar Institute of Engineering and Technology Punjab Patiala147004 India

Recent developments in 2D nanomaterials have greatly expanded their use in engineering applications. Graphitic carbon nitride (g-C3N4) shows a combination of electrical conductivity, sensing and luminescence abilities, biocompatibility, and chemical stability. The present study showcases the effectiveness of g-C3N4 as a photocatalyst for removing various organic molecules from water (such as methylene blue, 4-nitrophenol, and pharmaceutical drugs) and its potential use in dielectric applications when combined with an organic polymer (polyvinylidene fluoride;PVDF). XRD patterns confirmed the formation of g-C3N4 (which is complimented by the UV-Visible and FTIR results) and PVDF-g-C3N4 composite film. SEM-EDS verified the chemical homogeneity of the as-prepared g-C3N4 powder. Maximum photocatalytic degradation was observed for methylene blue dye (96.48%) with a half-life of 24.18 min, whereas the least degradation was detected for hydroxychloroquine (53.10%) with a half-life of 90.12 min after 120 min of UV-visible exposure. 10 wt% C3N4 reinforced PVDF thick films exhibited stable dielectric properties at low temperature (below 60°C) as compared to PVDF alone. At 1 kHz, the dielectric permittivity and tangent loss of the PVDF-g-C3N4 composites come out to be ∼6 and ∼0.05, respectively (at room temperature). The AC conductivity and activation energy of the synthesized composite was also studied. © 2023 IOP Publishing Ltd

关键词： Organic pollutants

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