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Widely Tunable Berry Curvature in the Magnetic Semimetal Cr1+δTe2

Advanced Materials 2023年第12期35卷

作者： Fujisawa, Yuita Pardo-Almanza, Markel Hsu, Chia-Hsiu Mohamed, Atwa Yamagami, Kohei Krishnadas, Anjana Chang, Guoqing Chuang, Feng-Chuan Khoo, Khoong Hong Zang, Jiadong Soumyanarayanan, Anjan Okada, Yoshinori Okinawa904-0495 Japan Department of Physics National Sun Yat-sen University Kaohsiung80424 Taiwan Physics Division National Center for Theoretical Sciences Taipei10617 Taiwan Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore637371 Singapore Center for Theoretical and Computational Physics National Sun Yat-sen University Kaohsiung80424 Taiwan Institute of High Performance Computing Agency for Science Technology and Research Singapore138632 Singapore Department of Physics and Astronomy University of New Hampshire DurhamNH 03824 United States Materials Science Program University of New Hampshire DurhamNH 03824 United States Department of Physics National University of Singapore Singapore117551 Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research Singapore138634 Singapore

Magnetic semimetals have increasingly emerged as lucrative platforms hosting spin-based topological phenomena in real and momentum spaces. Cr1+δTe2 is a self-intercalated magnetic transition metal dichalcogenide (TMD), which exhibits topological magnetism and tunable electron filling. While recent studies have explored real-space Berry curvature effects, similar considerations of momentum-space Berry curvature are lacking. Here, the electronic structure and transport properties of epitaxial Cr1+δTe2 thin films are systematically investigated over a range of doping, δ (0.33 – 0.71). Spectroscopic experiments reveal the presence of a characteristic semi-metallic band region, which shows a rigid like energy shift with δ. Transport experiments show that the intrinsic component of the anomalous Hall effect (AHE) is sizable and undergoes a sign flip across δ. Finally, density functional theory calculations establish a link between the doping evolution of the band structure and AHE: the AHE sign flip is shown to emerge from the sign change of the Berry curvature, as the semi-metallic band region crosses the Fermi energy. These findings underscore the increasing relevance of momentum-space Berry curvature in magnetic TMDs and provide a unique platform for intertwining topological physics in real and momentum spaces. © 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.

关键词： Density functional theory

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On a ‘Two Truths’ Phenomenon in Spectral Graph Clustering

arXiv

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arXiv 2018年

作者： Priebe, Carey E. Park, Youngser Vogelstein, Joshua T. Conroy, John M. Lyzinski, Vince Tang, Minh Athreya, Avanti Cape, Joshua Bridgeford, Eric Department of Applied Mathematics and Statistics Johns Hopkins University BaltimoreMD21218 United States Center for Imaging Science Johns Hopkins University BaltimoreMD21218 United States Human Language Technology Center of Excellence Johns Hopkins University BaltimoreMD21218 Department of Biomedical Engineering Johns Hopkins University BaltimoreMD21218 United States Institute for Defense Analyses Center for Computing Sciences BowieMD20715 United States Department of Mathematics and Statistics University of Massachusetts AmherstMA01003 United States Department of Biostatistics Johns Hopkins University BaltimoreMD21218 United States

Clustering is concerned with coherently grouping observations without any explicit concept of true groupings. Spectral graph clustering – clustering the vertices of a graph based on their spectral embedding – is commonly approached via K-means (or, more generally, Gaussian mixture model) clustering composed with either Laplacian or Adjacency spectral embedding (LSE or ASE). Recent theoretical results provide new understanding of the problem and solutions, and lead us to a ‘Two Truths’ LSE vs. ASE spectral graph clustering phenomenon convincingly illustrated here via a diffusion MRI connectome data set: the different embedding methods yield different clustering results, with LSE capturing left hemisphere/right hemisphere affinity structure and ASE capturing gray matter/white matter core-periphery structure. Copyright © 2018, The Authors. All rights reserved.

关键词： Graphic methods

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On (α + u β) constacyclic codes of length 4ps over Fpm + uFpm

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Journal of Algebra and its Applications 2019年第2期18卷

作者： Dinh, Hai Q. Nguyen, Bac T. Sriboonchitta, Songsak Vo, Thang M. Division of Computational Mathematics and Engineering Institute for Computational Science Ton Duc Thang University Ho Chi Minh City Viet Nam Faculty of Mathematics and Statistics Ton Duc Thang University Ho Chi Minh City Viet Nam Department of Mathematical Sciences Kent State University 4314 Mahoning Avenue Warren OH United States Department of Basic Sciences University of Economics and Business Administration Thai Nguyen University Thai Nguyen Province Viet Nam Nguyen Tat Thanh University 300 A Nguyen Tat Thanh Street Ho Chi Minh City Viet Nam Faculty of Economics Chiang Mai University Chiang Mai 52000 Thailand Department of Personnel and Organization Vinh University of Technology Education Vinh City Nghe An Viet Nam

For any odd prime p such that pm ≡ 3(mod 4), the structures of all (α+uβ)-constacyclic codes of length 4ps over the finite commutative chain ring pm + upm (u2 = 0) are established in term of their generator polynomials. When the unit (α + uβ) is a square, each (α + uβ)-constacyclic code of length 4ps is expressed as a direct sum of two constacyclic codes of length 2ps. In the main case that the unit (α + uβ) is not a square, it is shown that the ambient ring (pm+upm)[x] (x4ps-(α+uβ)) is a principal ideal ring. From that, the structure, number of codewords, duals of all such (α + uβ)-constacyclic codes are obtained. As an application, we identify all self-orthogonal, dual-containing, and the unique self-dual (α + uβ)-constacyclic codes of length 4ps over pm + upm. © 2019 World Scientific Publishing Company.

关键词： chain rings codes over rings Constacyclic codes dual codes repeated-root codes

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Explore the Origin of Spontaneous Symmetry Breaking from Adaptive Perturbation Method

arXiv

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arXiv 2022年

作者： Ma, Chen-Te Pan, Yiwen Zhang, Hui Department of Physics and Astronomy Iowa State University AmesIA50011 United States Asia Pacific Center for Theoretical Physics Pohang University of Science and Technology Gyeongsangbuk-do Pohang37673 Korea Republic of Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangdong Guangzhou510006 China School of Physics and Telecommunication Engineering South China Normal University Guangdong Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangdong Guangzhou510006 China The Laboratory for Quantum Gravity and Strings Department of Mathematics and Applied Mathematics University of Cape Town Private Bag Rondebosch7700 South Africa School of Physics Sun Yat-Sen University Guangdong Guangzhou510275 China

Spontaneous symmetry breaking occurs when the underlying laws of a physical system are symmetric, but the vacuum state chosen by the system is not. The (3+1)d 4 theory is relatively simple compared to other more complex theories, making it a good starting point for investigating the origin of non-trivial vacua. The adaptive perturbation method is a technique used to handle strongly coupled systems. The study of strongly correlated systems is useful in testing holography. It has been successful in strongly coupled QM and is being generalized to scalar field theory to analyze the system in the strong-coupling regime. The unperturbed Hamiltonian does not commute with the usual number operator. However, the quantized scalar field admits a plane-wave expansion when acting on the vacuum. While quantizing the scalar field theory, the field can be expanded into plane-wave modes, making the calculations more tractable. However, the Lorentz symmetry, which describes how physical laws remain the same under certain spacetime transformations, might not be manifest in this approach. The proposed elegant resummation of Feynman diagrams aims to restore the Lorentz symmetry in the calculations. The results obtained using this method are compared with numerical solutions for specific values of the coupling constant λ = 1, 2, 4, 8, 16. Finally, we find evidence for quantum triviality, where self-consistency of the theory in the UV requires λ = 0. This result implies that the 4 theory alone does not experience SSB, and the = 0 phase is protected under the RG-flow by a boundary of Gaussian fixed-points. Copyright © 2022, The Authors. All rights reserved.

关键词： Numerical methods

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Uniaxial plasmon polaritons via charge transfer at the graphene/CrSBr interface

arXiv

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arXiv 2024年

作者： Rizzo, Daniel J. Seewald, Eric Zhao, Fangzhou Cox, Jordan Xie, Kaichen Vitalone, Rocco A. Ruta, Francesco L. Chica, Daniel G. Shao, Yinming Shabani, Sara Telford, Evan J. Strasbourg, Matthew C. Darlington, Thomas P. Xu, Suheng Qiu, Siyuan Devarakonda, Aravind Taniguchi, Takashi Watanabe, Kenji Zhu, Xiaoyang Schuck, P. James Dean, Cory R. Roy, Xavier Millis, Andrew J. Cao, Ting Rubio, Angel Pasupathy, Abhay N. Basov, D.N. Department of Physics Columbia University New YorkNY10027 United States Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Theory Department Max Planck Institute for Structure and Dynamics of Matter Center for Free-Electron Laser Science Hamburg22761 Germany Department of Chemistry Columbia University New YorkNY10027 United States Department of Materials Science and Engineering University of Washington SeattleWA98195 United States Department of Mechanical Engineering Columbia University New YorkNY10027 United States Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Center for Computational Quantum Physics Flatiron Institute New YorkNY10010 United States Nano-Bio Spectroscopy Group Universidad del País Vasco UPV/EHU San Sebastián20018 Spain

Graphene is a privileged 2D platform for hosting confined light-matter excitations known as surface plasmon-polaritons (SPPs), as it possesses low intrinsic losses with a high degree of optical confinement. However, the inherently isotropic optical properties of graphene limit its ability to guide and focus SPPs, making it less suitable than anisotropic elliptical and hyperbolic materials as a platform for polaritonic lensing and canalization. Here, we present the graphene/CrSBr heterostructure as an engineered 2D interface that hosts highly anisotropic SPP propagation over a wide range of frequencies in the mid-infrared and terahertz. Using a combination of scanning tunneling microscopy (STM), scattering-type scanning near-field optical microscopy (s-SNOM), and first-principles calculations, we demonstrate mutual doping in excess of 1013 cm–2 holes/electrons between the interfacial layers of graphene/CrSBr heterostructures. SPPs in graphene activated by charge transfer interact with charge-induced anisotropic intra- and interband transitions in the interfacial doped CrSBr, leading to preferential SPP propagation along the quasi-1D chains that compose each CrSBr layer. This multifaceted proximity effect both creates SPPs and endows them with anisotropic transport and propagation lengths that differ by an order-of-magnitude between the two in-plane crystallographic axes of CrSBr. © 2024, CC BY.

关键词： Charge transfer

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On the Elastic Properties of Single-Walled Phagraphene Nanotubes

arXiv

引用

arXiv 2020年

作者： Pereira, M.L. de Sousa, J.M. Brandão, W.H.S. Aguiar, A.L. Bizao, R.A. Ribeiro, L.A. Galvão, D.S. Institute of Physics University of Brasília Brasília70910-900 Brazil Federal Institute of Education Science and Technology of Piauí São Raimundo NonatoPiauí Brazil Physics Department Piauí Federal University TeresinaPiauÃŋ64049-550 Brazil Institute of Mathematics and Computer Sciences University of São Paulo São Carlos São Paulo Brazil PPGCIMA Campus Planaltina University of Brasília Brasília73345-010 Brazil Applied Physics Department ’Gleb Wataghin’ Institute of Physics State University of Campinas CampinasSP13083-970 Brazil Center for Computing in Engineering & Sciences State University of Campinas Campinas SP13083-970 Brazil

Phagraphene (PhaG) is a quasi-planar 2D structure composed of 5 − 6 − 7 ring sequence. We have investigated the structural and mechanical properties of phagraphene nanotubes (PhaNTs) through fully atomistic reactive molecular dynamics (MD) simulations. For comparison purposes, the results were also contrasted to similar carbon nanotubes (CNTs). Results showed that PhaNTs and CNTs present similar brittle fracture mechanisms. The Young’s modulus values obtained for PhaNTs were smaller than the corresponding ones for CNTs. Both, PhaNTs and CNTs, present equivalent fracture strains ranging between 15%-20%. For the ultimate strength values, CNTs present values about 30% higher than the corresponding ones for *** Codes 00-XX Copyright © 2020, The Authors. All rights reserved.

关键词： Molecular dynamics

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TAMM: Tensor algebra for many-body methods

arXiv

引用

arXiv 2022年

作者： Mutlu, Erdal Panyala, Ajay Gawande, Nitin Bagusetty, Abhishek Kim, Jinsung Kowalski, Karol Bauman, Nicholas P. Peng, Bo Brabec, Jiri Krishnamoorthy, Sriram Glabe, Jeffrey Pathak, Himadri Advanced Computing Mathematics and Data Division Pacific Northwest National Laboratory RichlandWA99354 United States Intel Corporation RichlandWA99354 United States Argonne Leadership Computing Facility Argonne National Laboratory ArgonneIL60439 United States School of Computer Science and Engineering Chung-Ang University Seoul06974 Korea Republic of Physical Sciences Division Pacific Northwest National Laboratory RichlandWA99354 United States J. Heyrovský Institute of Physical Chemistry Academy of Sciences of the Czech Republic Prague 8182 23 Czech Republic Google Inc. Mountain ViewCA94043 United States

Tensor algebra operations such as contractions in computational chemistry consume a significant fraction of the computing time on large-scale computing platforms. The widespread use of tensor contractions between large multidimensional tensors in describing electronic structure theory has motivated the development of multiple tensor algebra frameworks targeting heterogeneous computing platforms. In this paper, we present Tensor Algebra for Many-body Methods (TAMM), a framework for productive and performance-portable development of scalable computational chemistry methods. TAMM decouples the specification of the computation from the execution of these operations on available high-performance computing systems. With this design choice, the scientific application developers (domain scientists) can focus on the algorithmic requirements using the tensor algebra interface provided by TAMM, whereas high-performance computing developers can direct their attention to various optimizations on the underlying constructs, such as efficient data distribution, optimized scheduling algorithms, and efficient use of intra-node resources (e.g., graphics processing units). The modular structure of TAMM allows it to support different hardware architectures and incorporate new algorithmic advances. We describe the TAMM framework and our approach to the sustainable development of scalable ground- and excited-state electronic structure methods. We present case studies highlighting the ease of use, including the performance and productivity gains compared to other frameworks. © 2022, CC BY-NC-ND.

关键词： computational chemistry

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Applications of Machine Learning to Lattice Quantum Field Theory

arXiv

引用

arXiv 2022年

作者： Boyda, Denis Calì, Salvatore Foreman, Sam Funcke, Lena Hackett, Daniel C. Lin, Yin Aarts, Gert Alexandru, Andrei Jin, Xiao-Yong Lucini, Biagio Shanahan, Phiala E. Leadership Computing Facility Argonne National Laboratory ArgonneIL60439 United States The NSF AI Institute for Artificial Intelligence and Fundamental Interactions Center for Theoretical Physics Massachusetts Institute of Technology CambridgeMA02139 United States United States Department of Physics Swansea University SwanseaSA2 8PP United Kingdom 38123 Italy Physics Department The George Washington University WashingtonDC20052 United States Department of Physics University of Maryland College ParkMD20742 United States Computational Science Division Argonne National Laboratory ArgonneIL60439 United States Department of Mathematics Swansea University Bay Campus SwanseaSA1 8EN United Kingdom Swansea Academy of Advanced Computing Swansea University Bay Campus SwanseaSA1 8EN United Kingdom

There is great potential to apply machine learning in the area of numerical lattice quantum field theory, but full exploitation of that potential will require new strategies. In this white paper for the Snowmass community planning process, we discuss the unique requirements of machine learning for lattice quantum field theory research and outline what is needed to enable exploration and deployment of this approach in the future. Copyright © 2022, The Authors. All rights reserved.

关键词： Machine learning

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Effects of the initial perturbations on the Rayleigh-Taylor-Kelvin-Helmholtz instability system

引用

Frontiers of Physics 2022年第3期 76-88页

作者：陈锋许爱国张玉东甘延标刘冰冰王爽 School of Aeronautics Shan Dong Jiaotong University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking University State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology School of Mechanics and Safety Engineering Zhengzhou University Hebei Key Laboratory of Trans-Media Aerial Underwater Vehicle North China Institute of Aerospace Engineering Naval Architecture and Port Engineering College Shan Dong Jiaotong University School of Science Shandong Jianzhu University

The effects of initial perturbations on the Rayleigh-Taylor instability（RTI）,Kelvin-Helmholtz instability（KHI）,and the coupled Rayleigh-Taylor-Kelvin-Helmholtz instability（RTKHI） systems are investigated using a multiple-relaxation-time discrete Boltzmann *** different perturbation interfaces are designed to study the effects of the initial perturbations on the instability *** is found that the initial perturbation has a significant influence on the evolution of *** sharper the interface,the faster the growth of bubble or *** the influence of initial interface shape on KHI evolution can be *** on the mean heat flux strength D3,1,the effects of initial interfaces on the coupled RTKHI are examined in *** research is focused on two aspects:（i） the main mechanism in the early stage of the RTKHI,（ii） the transition point from KHI-like to RTI-like for the case where the KHI dominates at earlier time and the RTI dominates at later *** is found that the early main mechanism is related to the shape of the initial interface,which is represented by both the bilateral contact angle θ1and the middle contact angle θ*** increase of θ1and the decrease ofθ2have opposite effects on the critical *** θ2remains roughly unchanged at 90 degrees,if θ1is greater than 90 degrees（such as the parabolic interface）,the critical shear velocity increases with the increase of θ1,and the ellipse perturbation is its limiting case;If θ1is less than 90 degrees（such as the inverted parabolic and the inverted ellipse disturbances）,the critical shear velocities are basically the same,which is less than that of the sinusoidal and sawtooth *** influence of inverted parabolic and inverted ellipse perturbations on the transition point of the RTKHI system is greater than that of other interfaces:（i） For the same amplitude,the smaller the contact angle θ1,the later the transition point appears;（ii） For the same interface morphology,the distu

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Diabetes disease prediction using decision tree for feature selection

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Journal of Physics: Conference Series 2021年第6期1964卷

作者： Jayakumar Sadhasivam V Muthukumaran J Thimmia Raja Rose Bindu Joseph Meram Munirathanam J M Balajee School of Information Technology and Engineering (SITE) Vellore Institute of Technology Vellore India Department of Mathematics School of Applied Science REVA University Bengaluru – 64. School of Computing Kalasalingam Academy of Research and Education Tamilnadu-626128 India Department of Mathematics Christ Academy Institute for Advance Studies Department of Mathematics Rajiv Gandhi University of Knowledge Technologies School of Information Technology and Engineering Vellore Institute of Technology Vellore India

In this paper more than one approaches are evaluated to optimise machine learning models for diabetes disease diagnosis. The main goal is to sort the medical data computation and choose the most suitable parameters to construct a faster and more perfect model using feature selection. Reducing the number of features to construct a model could direct to more useful machine learning algorithms which helps the doctors to focus on what are the most significant assessment to take into story. Feature selection is one of the process in machine learning which choose a subset of topical features namely variables for construction of models. In this research paper we use three feature selection techniques like Recursive Feature Elimination (RFE), Genetic Algorithm (GA) and Burota Package. After using feature selection at the end we use Decision Tree to predict the diagnosis Diabetes using a dataset named Pima Indian Diabetes Dataset and verify the performance of result model.

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