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Journal of Magnetism and Magnetic materials 2020年 493卷

作者： Baoshan Cui Hao Wu Meixia Chang Jijun Yun Yalu Zuo Meizhen Gao Kang L. Wang Li Xi Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education & School of Physical Science and Technology Lanzhou University Lanzhou 730000 People’s Republic of China Department of Electrical and Computer Engineering University of California Los Angeles CA 90095 USA

Domain wall (DW) motion via current induced spin-orbit torque (SOT) and/or a magnetic field in ferromagnet/heavy metal heterostructure has attracted abundant interests due to its potential applications in magnetic memories and logic devices. In this work, we study the influence of the depinning energy barrier on DW motion in the creep regime using the polar magneto-optical Kerr microscopy in the Cr layer decorated Pt/Co/Ta structure. We find that although the SOT efficiency shows a significant enhancement in the Pt/Co/Cr/Ta system, but the current-induced DW motion efficiency still shows an attenuation. We confirm that this unexpected result is caused by the enhanced pinning energy barrier, extracted from the relationship between the cumulative depinning probability ( P d ) and the depinning time ( t ). Moreover, the relationship between P d and t exhibits preferred exponential distribution, indicating that a single energy barrier governs the depinning behavior in our systems. We also reveal that the energy barrier depends on the interface between the ferromagnet and heavy metal. Our study suggests that the current-induced DW motion efficiency is not only determined by the SOT efficiency, but also the depinning energy barrier.

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A Novel modeling approach for all-dielectric metasurfaces using deep neural networks

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arXiv 2019年

作者： An, Sensong Fowler, Clayton Zheng, Bowen Shalaginov, Mikhail Y. Tang, Hong Li, Hang Zhou, Li Ding, Jun Agarwal, Anuradha Murthy Rivero-Baleine, Clara Richardson, Kathleen A. Gu, Tian Hu, Juejun Zhang, Hualiang Department of Electrical & Computer Engineering University of Massachusetts Lowell LowellMA United States Department of Materials Science & Engineering Massachusetts Institute of Technology CambridgeMA United States Shanghai Key Laboratory of Multidimensional Information Processing East China Normal University Shanghai China Lockheed Martin Corporation OrlandoFL United States CREOL University of Central Florida OrlandoFL United States

Metasurfaces have become a promising means for manipulating optical wavefronts in flat and high-performance optical devices. Conventional metasurface device design relies on trial-and-error methods to obtain target electromagnetic (EM) response, an approach that demands significant efforts to investigate the enormous number of possible meta-atom structures. In this paper, a deep neural network approach is introduced that significantly improves on both speed and accuracy compared to techniques currently used to assemble metasurface-based devices. Our neural network approach overcomes three key challenges that have limited previous neural-network-based design schemes: input/output vector dimensional mismatch, accurate EM-wave phase prediction, as well as adaptation to 3-D dielectric structures, and can be generically applied to a wide variety of metasurface device designs across the entire electromagnetic spectrum. Using this new methodology, examples of neural networks capable of producing on-demand designs for meta-atoms, metasurface filters, and phase-change reconfigurable metasurfaces are demonstrated. Copyright © 2019, The Authors. All rights reserved.

关键词： Deep neural networks

The CMS Statistical Analysis and Combination Tool: Combine

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Computing and Software for Big science 2024年第1期8卷 1-45页

作者： Zhokin, A. Zhizhin, I. Zarubin, A. Yuldashev, B.S. Voytishin, N. Vorotnikov, G. Vorobyev, A. Volkov, P. Uzunian, A. Uvarov, L. Toropin, A. Tlisova, I. Teryaev, O. Terkulov, A. Tcherniaev, E. Sulimov, V. Sosnov, D. Smirnov, V. Slabospitskii, S. Skovpen, Y. Shulha, S. Shmatov, S. Shalaev, V. Savrin, V. Savina, M. Radchenko, O. Popov, V. Polikarpov, S. Perfilov, M. Perelygin, V. Palichik, V. Oreshkin, V. Obraztsov, S. Nikitenko, A. Murzin, V. Matveev, V. Malakhov, A. Makarenko, V. Lychkovskaya, N. Levchenko, P. Lanev, A. Krasnikov, N. Kozyrev, A. Korenkov, V. Konstantinov, D. Kodolova, O. Klyukhin, V. Kirsanov, M. Kirpichnikov, D. Kirakosyan, M. Kim, V. Karneyeu, A. Karjavine, V. Kachanov, V. Ivanov, Y. Gribushin, A. Gorbunov, I. Golutvin, I. Golubev, N. Golovtcov, V. Gninenko, S. Gavrilov, V. Gavrilov, G. Dudko, L. Dubinin, M. Druzhkin, D. Dimova, T. Dermenev, A. Chistov, R. Chekhovsky, V. Chadeeva, M. Bunichev, V. Budkouski, D. Borshch, V. Boos, E. Blinov, V. Babaev, A. Azarkin, M. Aushev, T. Andreev, Yu. Andreev, V. Alexakhin, V. Afanasiev, S. Warden, A. Vetens, W. Tsoi, H.F. Teague, D. Smith, W.H. Sharma, V. Shang, V. Savin, A. Pinna, D. Pétré, L. Parida, G. Mondal, S. Mohammadi, A. Mallampalli, A. Sreekala, J. Madhusudanan Loveless, R. Lanaro, A. Koraka, C.K. Herve, A. Herndon, M. He, H. Galloni, C. Everaerts, P. De Bruyn, I. Dasu, S. Bose, T. Black, K. Banerjee, S. Aravind, A. Karchin, P.E. Bhattacharya, S. Neu, C. Ledovskoy, A. Hirosky, R. Hakala, J. Cox, B. Cardwell, B. Viinikainen, J. Velkovska, J. Tuo, S. Sheldon, P. Romeo, F. Melo, A. Elayavalli, R. Kunnawalkam Johns, W. Gurrola, A. Greene, S. Chen, Y. Appelt, E. Volobouev, I. Peltola, T. Mankel, A. Lee, S.W. Lamichhane, K. Kazhykarim, Y. Hussain, A. Hegde, V. Gogate, N. Damgov, J. Akchurin, N. Safonov, A. Rathjens, D. Overton, D. Mueller, R. Luo, S. Kim, H. Kamon, T. Huang, T. Gilmore, J. Eusebi, R. Bouhali, O. Akhter, T. Ahmad, M. Aebi, D. Spanier, S. Nibigira, E. Lee, L. Karunarathna, N. Kanuganti, A.R. Holmes, T. Higginbotham, S. Fiorendi, S. Delannoy Yerevan Physics Institute Yerevan Armenia Institut für Hochenergiephysik Vienna Austria Universiteit Antwerpen Antwerpen Belgium Vrije Universiteit Brussel Brussel Belgium Université Libre de Bruxelles Bruxelles Belgium Ghent University Ghent Belgium Université Catholique de Louvain Louvain-la-Neuve Belgium Centro Brasileiro de Pesquisas Fisicas Rio de Janeiro Brazil Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Universidade Estadual Paulista Universidade Federal do ABC São Paulo Brazil Institute for Nuclear Research and Nuclear Energy Bulgarian Academy of Sciences Sofia Bulgaria University of Sofia Sofia Bulgaria Instituto De Alta Investigación Universidad de Tarapacá Casilla 7 D Arica Chile Beihang University Beijing China Department of Physics Tsinghua University Beijing China Institute of High Energy Physics Beijing China State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China Guangdong Provincial Key Laboratory of Nuclear Science and Guangdong-Hong Kong Joint Laboratory of Quantum Matter South China Normal University Guangzhou China Sun Yat-Sen University Guangzhou China University of Science and Technology of China Hefei China Nanjing Normal University Nanjing China Key Laboratory of Nuclear Physics and Ion-beam Application (MOE) Institute of Modern Physics Fudan University Shanghai China Zhejiang University Hangzhou Zhejiang China Universidad de Los Andes Bogota Venezuela Universidad de Antioquia Medellin Colombia Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture University of Split Split Croatia Faculty of Science University of Split Split Croatia Institute Rudjer Boskovic Zagreb Croatia University of Cyprus Nicosia Cyprus Charles University Prague Czech Republic Universidad San Francisco de Quito Quito Ecuador Egyptian Network of High Energy Physics Academy of Scientific Research and Technology of the Arab Republic of Egypt Cairo Egypt Center for High

This paper describes the Combine software package used for statistical analyses by the CMS Collaboration. The package, originally designed to perform searches for a Higgs boson and the combined analysis of those searches, has evolved to become the statistical analysis tool presently used in the majority of measurements and searches performed by the CMS Collaboration. It is not specific to the CMS experiment, and this paper is intended to serve as a reference for users outside of the CMS Collaboration, providing an outline of the most salient features and capabilities. Readers are provided with the possibility to run Combine and reproduce examples provided in this paper using a publicly available container image. Since the package is constantly evolving to meet the demands of ever-increasing data sets and analysis sophistication, this paper cannot cover all details of Combine. However, the online documentation referenced within this paper provides an up-to-date and complete user guide. © CERN, for the benefit of the CMS Collaboration 2024.

关键词： CMS Combine Higgs Higgs boson Statistics

Effects of single vacancy defects on 1/f noise in grapbene/b-BN FETs 76

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Effects of single vacancy defects on 1/f noise in grapbene/b...

76th Device Research Conference, DRC 2018

作者： Wu, Ting Alharbi, Abdullah Taniguchi, Takashi Watanabe, Kenji Shahricrdi, Davood Electrical and Computer Engineering Department New York University BrooklynNY11201 United States National Institute of Materials Science 1-1 Namiki Tsukuba Ibaraki305-0044 Japan Center for Quantum Phenomena Physics Department New York University New YorkNY10003 United States

ISBN: (纸本)9781538630280

SP2 carbon materials, including carbon nanotubes and graphene, have been used extensively for making highly sensitive biochemical field-effect transistor (FET) sensors. Previous studies suggest that structural disorders in these materials enhance the device sensitivity. Despite many studies on device sensitivity in relation to structural defects, only a few studies have examined the effect of defects on low-frequency noise in graphene FETs [1]. However, no study has yet investigated the correlation between the specific type defects, e.g. single vacancy defects, and the low-frequency noise characteristics of graphene transistors. Here, we systematically study the connection between the concentration of single vacancy defects, the low-frequency noise and carrier transport in graphene FETs. © 2018 IEEE.

关键词： Graphene

Generation and Hall effect of skyrmions enabled via using nonmagnetic point contacts

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arXiv 2019年

作者： Wang, Zidong Zhang, Xichao Xia, Jing Zhao, Le Wu, Keyu Yu, Guoqiang Wang, Kang L. Liu, Xiaoxi Te Velthuis, Suzanne G. E. Hoffmann, Axel Zhou, Yan Jiang, Wanjun State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China School of Science and Engineering Chinese University of Hong Kong Shenzhen Guangdong518172 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Department of Electrical Engineering University of California Los AngelesCA90095 United States Department of Electrical and Computer Engineering Shinshu University 4-17-1 Wakasato Nagano380-8553 Japan Materials Science Division Argonne National Laboratory LemontIL60439 United States

To enable functional skyrmion-based spintronic devices, the controllable generation and manipulation of skyrmions is essential. While the generation of skyrmions by using a magnetic geometrical constriction has already been demonstrated, this approach is difficult to combine with a subsequent controlled manipulation of skyrmions. The high efficiency of skyrmion generation from magnetic constrictions limits the useful current density, resulting in stochastic skyrmion motion, which may obscure topological phenomena such as the skyrmion Hall effect. In order to address this issue, we designed a nonmagnetic conducting Ti/Au point contact in devices made of Ta/CoFeB/TaOx trilayer films. By applying high voltage pulses, we experimentally demonstrated that skyrmions can be dynamically generated. Moreover, the accompanied spin topology dependent skyrmion dynamics-the skyrmion Hall effect is also experimentally observed in the same devices. The creation process has been numerically reproduced through micromagnetic simulations in which the important role of skyrmion-antiskyrmion pair generation is identified. The motion and Hall effect of the skyrmions, immediately after their creation is described using a modified Thiele equation after taking into account the contribution from spatially inhomogeneous spin-orbit torques and the Magnus force. The simultaneous generation and manipulation of skyrmions using a nonmagnetic point contact could provide a useful pathway for designing novel skyrmion based devices. Copyright © 2019, The Authors. All rights reserved.

关键词： Topology

Identifying the fingerprints of topological states by tuning magnetoresistance in a semimetal: the case of topological half-Heusler Pt1−xAuxLuSb

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arXiv 2020年

作者： Chatterjee, Shouvik de Lima, Felipe Crasto Logan, John A. Fang, Yuan Inbar, Hadass Goswami, Aranya Dempsey, Connor Dong, Jason Khalid, Shoaib Brown-Heft, Tobias Chang, Yu-Hao Guo, Taozhi Pennachio, Daniel Wilson, Nathaniel Chikara, Shalinee Suslov, Alexey Fedorov, Alexei V. Read, Dan Cano, Jennifer Janotti, Anderson Palmstrøm, Christopher J. Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States Department of Condensed Matter Physics and Materials Science Tata Institute of Fundamental Research Homi Bhabha Road Mumbai400005 India Department of Materials Science and Engineering University of Delaware NewarkDE19716 United States Instituto de Física Universidade Federal de Uberlândia C.P. 593 Uberlândia MG 38400-592 Brazil Materials Department University of California Santa BarbaraCA93106 United States Department of Physics and Astronomy Stony Brook University Stony BrookNY11974 United States Department of Physics and Astronomy University of Delaware NewarkDE19716 United States Department of Physics University of California Santa BarbaraCA93106 United States National High Magnetic Field Laboratory TallahasseeFL32310 United States Advanced Light Source Lawrence Berkeley National Laboratory BerkeleyCA94720 United States School of Physics and Astronomy Cardiff University CardiffCF24 3AA United Kingdom Center for Computational Quantum Physics Flatiron Institute New YorkNY10010 United States California NanoSystems Institute University of California Santa BarbaraCA93106 United States

Topological materials often exhibit remarkably linear, non-saturating magnetoresistance (LMR), which is both of scientific and technological importance. However, the role of topologically nontrivial states in the emergence of such a behaviour has eluded clear demonstration in experiments. Here, by reducing the coupling between the topological surface states (TSS) and the bulk carriers we controllably tune the LMR behavior in Pt1−xAuxLuSb into distinct plateaus in Hall resistance, which we show arise from a quantum Hall phase. This allowed us to reveal how smearing of the Landau levels, which otherwise give rise to a quantum Hall phase, results in an LMR behavior due to strong interaction between the TSS with a positive g-factor and the bulk carriers. We establish that controlling the coupling strength between the surface and the bulk carriers in topological materials can bring about dramatic changes in their magnetotransport behavior. In addition, our work outlines a strategy to reveal macroscopic physical observables of TSS in compounds with a semi-metallic bulk band structure, as is the case in multi-functional Heusler compounds, thereby opening up opportunities for their utilization in hybrid quantum structures. Copyright © 2020, The Authors. All rights reserved.

关键词： Topology

Suppressing material loss for functional nanophotonics using bandgap engineering

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arXiv 2019年

作者： Wang, Mingsong Krasnok, Alex Lepeshov, Sergey Hu, Guangwei Jiang, Taizhi Fang, Jie Korgel, Brian A. Alù, Andrea Zheng, Yuebing Walker Department of Mechanical Engineering and Texas Materials Institute University of Texas at Austin AustinTX78712 United States Advanced Science Research Center City University of New York Photonics InitiativeNY10031 United States Itmo University St. Petersburg197101 Russia McKetta Department of Chemical Engineering University of Texas at Austin AustinTX78712 United States Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore

All-dielectric nanoantennas have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts to the visible range is hindered by a larger absorption coefficient of Si and other high-index semiconductors, thus encouraging the search for alternative dielectrics for nanophotonics. In this paper, we employ bandgap engineering to synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features for functional nanophotonics. We observe significant material loss suppression in a-Si:H NPs in the visible range caused by hydrogenation-induced bandgap renormalization, producing resonant modes in single a-Si:H NPs with Q factors up to ~100, in the visible and near-IR range for the first time. In order to demonstrate light-matter interaction enhancement, we realize highly tunable all-dielectric nanoantennas coupling them to photochromic spiropyran (SP) molecules. We show ~70% reversible all-optical tuning of light scattering at the high-Q resonant mode, along with minor tunability when out of resonance. This remarkable all-optical tuning effect is achieved under a low incident light intensity ~3.8 W/cm2 for UV light and ~1.1×102 W/cm2 for green light. Copyright © 2019, The Authors. All rights reserved.

关键词： Infrared devices

Identifying irregularity electricity usage of customer behaviors using logistic regression and linear discriminant analysis 3

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Identifying irregularity electricity usage of customer behav...

3rd International Conference on science in Information Technology, ICSITech 2017

作者： Lawi, Armin Wungo, Supriyadi La Manjang, Salama Department of Computer Science Post-graduate Program of Electrical Engineering Dept. Electrical Engineering Universitas Hasanuddin Makassar Indonesia

ISBN: (纸本)9781509058662

This study aims to implement a machine learning technique in identifying the irregularities of customer behavior on the use of prepaid electricity pulses. The methods used are Linear Discriminant Analysis and Logistic Regression. The performance of the classification system will be evaluated using the 10-fold cross-validation technique. Validation results are measured using accuracy, precision and recall values. In this research shows that the use of machine learning technique has a good performance in classification of electrical consumption behavior. Experimental results with the different amount of data testing indicate that Logistic Regression method has high accuracy, precision, and recall value when compared with Linear Discriminant Analysis that is 100%. This is due to Logistic Regression method can predict irregularities accurately because the addition of the amount of data does not affect the performance of the method. © 2017 IEEE.

关键词： Regression analysis

Structural color 3d printing by shrinking photonic crystals

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arXiv 2019年

作者： Liu, Yejing Wang, Hao Ho, Jinfa Ng, Ryan C. Ng, Ray J. H. Hall-Chen, Valerian H. Koay, Eleen H. H. Dong, Zhaogang Liu, Hailong Qiu, Cheng-Wei Greer, Julia R. Yang, Joel K. W. Engineering Product Development Singapore University of Technology and Design Singapore487372 Singapore Division of Engineering and Applied Science California Institute of Technology PasadenaCA91125 United States Nanofabrication Department Institute of Materials Research and Engineering Singapore138634 Singapore Rudolf Peierls Centre for Theoretical Physics University of Oxford OxfordOX1 3PU United Kingdom Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore

The rings, spots and stripes found on some butterflies, Pachyrhynchus weevils, and many chameleons are notable examples of natural organisms employing photonic crystals to produce colorful patterns. Despite advances in nanotechnology, we still lack the ability to print arbitrary colors and shapes in all three dimensions at this microscopic length scale. Commercial nanoscale 3D printers based on two-photon polymerization are incapable of patterning photonic crystal structures with the requisite ~300 nm lattice constant to achieve photonic stopbands/bandgaps in the visible spectrum and generate colors. Here, we introduce a means to produce 3D-printed photonic crystals with a 5x reduction in lattice constants (periodicity as small as 280 nm), achieving sub-100-nm features with a full range of colors. The reliability of this process enables us to engineer the bandstructures of woodpile photonic crystals that match experiments, showing that observed colors can be attributed to either slow light modes or stopbands. With these lattice structures as 3D color volumetric elements (voxels), we printed 3D microscopic scale objects, including the first multi-color microscopic model of the Eiffel Tower measuring only 39-ìm tall with a color pixel size of 1.45 ìm. The technology to print 3D structures in color at the microscopic scale promises the direct patterning and integration of spectrally selective devices, such as photonic crystal-based color filters, onto free-form optical elements and curved surfaces. Copyright © 2019, The Authors. All rights reserved.

关键词： 3D printers

Current-induced helicity reversal of a single skyrmionic bubble chain in a nanostructured frustrated magnet

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arXiv 2019年

作者： Hou, Zhipeng Zhang, Qiang Zhang, Xichao Xu, Guizhou Xia, Jing Ding, Bei Li, Hang Zhang, Senfu Batra, Nitin M. Costa, Pedro M.F.J. Liu, Enke Wu, Guangheng Ezawa, Motohiko Liu, Xiaoxi Zhou, Yan Zhang, Xixiang Wang, Wenhong Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Institute for Advanced Materials South China Academy of Advanced Optoelectronics South China Normal University Guangzhou510006 China Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia School of Science and Engineering Chinese University of Hong Kong Shenzhen Guangdong518172 China School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Applied Physics University of Tokyo 7-3-1 Hongo Tokyo113-8656 Japan Department of Electrical and Computer Engineering Shinshu University 4-17-1 Wakasato Nagano380-8553 Japan

Helicity indicates the in-plane magnetic-moment swirling direction of a skyrmionic configuration. The ability to reverse the helicity of a skyrmionic bubble via purely electrical means has been predicted in frustrated magnetic systems, however its experimental observation has remained challenging. Here, we experimentally demonstrate the current-driven helicity reversal of the skyrmionic bubble in a nanostructured frustrated Fe3Sn2 magnet. The critical current density required to trigger the helicity reversal is 109 - 1010 A/m2, with a corresponding pulse-width varying from 1 μs to 100 ns. Computational simulations reveal that both the pinning effect and dipole-dipole interaction play a crucial role in the helicity-reversal process. Copyright © 2019, The Authors. All rights reserved.

关键词： Magnetic moments