Quantum Materials for Modern Magnetism & Spintronics (Q3MS)
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Workshop on Computational Physics and Materials Science
Workshop on Computational Physics and Materials Science: Total Energy and Force Methods 2020 Donostia-San Sebastián, Spain January 8-10, 2020 Institutional support and funding Preface This workshop is organized within the well-established “Total Energy and Force” conference series, which is held at ICTP in Trieste every odd year, and at a different place in the world every even year. The previous most recent workshops of this series outside Trieste took place in Barcelona (2012), Lausanne (2014), Luxembourg (2016) and Cambridge (2018). The main objective of this event is to identify new developments and topics in the field of electronic-structure methods from the first-principles perspective, their diverse applications, and its mathematical foundations. As such, it provides a great opportunity to assemble a wide range of leading scientists working on different aspects of computational material science. The workshop aims to cover the following topics: • Electron-phonon • Dielectrics • 2D materials • Correlation effects • Superconductivity • Topological materials • Transport properties • Excitations Organizing committee • Aran Garcia-Lekue, DIPC • Ivo Souza, UPV/EHU • Ion Errea, UPV/EHU Scientific advisory board • O. Akin-Ojo, University of Ibadan • E. Artacho, University of Cambridge & Nanogune • W. Andreoni, Ecole Polytechnique Fédérale de Lausanne • S. Biermann, Ecole Polytechnique, Palaiseau • R. Car, Princeton University • C. Filippi, University of Twente • M. Finnis, Imperial College • R. Gebauer, International Centre for Theoretical Physics • X.-G. Gong, Fudan University • J. Ihm, Seoul National University • E. Koch, Forschungszentrum Jülich • G. Kresse, University of Vienna • R. M. Martin, Stanford University • F. Mauri, University “La Sapienza” • A. Mostofi, Imperial College London • S. Narasimhan, JNCASR Bangalore • J. B. -
Graphene and 2DM Online Conference (GO2020): Fundamental Research Insights
Fundamental Research Insights JULY 07, 2020 Aachen Graphene & 2D-Materials Center From basic research to innovation Digital Hardware ■ Electronics for neuromorphic computing ■ Sensor technology for autonomous driving and IoT ■ Optoelectronics for high speed data communication ■ Electronics for wearables and implantables AMO AMO GmbH Otto-Blumenthal-Straße 25 ■ D-52074 Aachen ■ Germany Phone +49 241 88 67-125 ■ Fax +49 241 88 67-571 [email protected] ■ www.amo.de F OREWORD On behalf of the Organising Committee we take great pleasure in welcoming you for the 1st edition of the Graphene and 2DM Online Conference (GO2020): Fundamental Research Insights. Graphene and 2D Materials have a huge potential to impact established industrial sectors, building new emerging industries and niche segments and creating economic value. The one-day Graphene and 2DM Online conference (GO2020) will present the most recent advances in fundamental research in electronics, energy storage, biohealth, composites, coatings or sensors. 11 high profile talks from worldwide most influential academia experts in the Graphene and 2DM sector will present speeches in this international event on how advanced materials will change the future of technology and impact positively our daily life. GO2020 will be a one-day online event that means to gather the key players of the Graphene and 2DM Community and related sectors. This event is launched following the success of previous Grapheneconf editions and considering that all major scientific and technological conferences are being cancelled or postponed worldwide until the end of 2020. We are indebted to the following Company for their help and financial support: AMO GmbH (Germany) We also would like to thank all the speakers and participants that join us this year. -
Flat Band Moirés
European Physical Society Condensed Matter Division Flat Band Moirés Leni Bascones1, Dmitri Efetov2, Johannes Lischner3 1 Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC 2 Institute of Photonic Sciences ICFO 3 Imperial College London Wednesday, September, 2nd 9:30-10:10 Correlated, insulating and superconducting States in twisted bilayer graphene Below the Magic Angle. Jeanie Lau (invited). 10:10-10:30 Flat band superconductivity in twisted bilayer graphene. Tero Heikkilä, T. Peltonen, A. Julku, R. Ojajärvi, L. Long, P. Törmä. 10:30-10:50 Band structure and insulating states driven by the Coulomb interactions in twisted bilayer graphene. Tommaso Cea, F. Guinea. 10:50-11:10 Interactions in magic-angle twisted bilayer graphene. María José Calderón, E. Bascones. 11:10-11:30 Evidence of weakly dispersive bands in twisted bilayer graphene from nano-ARPES. Simone Lisi, X. Lu, T. Benschop, T. A. de Jong, P. Stepanov, J. R. Duran, Fl. Margot, I. Cucchi, E. Cappelli, A. Hunter, A. Tamai, V. Kandyba, A. Giampietri, A. Barinov, Johannes Jobst, Vincent Stalman, M. Leeuwenhoek, K. Watanabe, T. Taniguchi, L. Rademaker, S. J. van der Molen, M. Allan, D. K. Efetov, F. Baumberger. 11:30-11:50 Marginal Fermi liquid in twisted bilayer graphene José González, T. Stauber. 11:50-12:10 Inconmensurability induced sub-ballistic states in twisted bilayer graphene. Miguel de Jesús Mestre Gonçalves, H. Z. Olyaei1, B. Amorim, R. Mondaini, P. Ribeiro, E. V. Castro. 12:10-12:30 Strain induced excitonic instability in twisted bilayer graphene. Héctor Ochoa. Thursday, September 3rd 9:30-10:10 Moiré physics and symmetry breaking in magnetically encapsulated van der Waals structures. -
2015 Annual Report
2015 AMERICAN PHYSICAL SOCIETY ANNUAL TM ADVANCING PHYSICS REPORT TM THE AMERICAN PHYSICAL SOCIETY STRIVES TO Be the leading voice for physics and an authoritative source of physics information for the advancement of physics and the benefit of humanity Collaborate with national scientific societies for the advancement of science, science education, and the science community Cooperate with international physics societies to promote physics, to support physicists worldwide, and to foster international collaboration Have an active, engaged, and diverse membership, and support the activities of its units and members © 2016 American Physical Society During 2015, APS worked to institute the governance objective: “the advancement and diffusion of the knowledge changes approved by the membership in late 2014. In of physics.” APS is fully committed to the principles of OA accordance with the new Constitution & Bylaws, in to the extent that we can continue to support the production February the Board appointed our first Chief Executive of high-quality peer-reviewed journals. For many years APS Officer—Kate Kirby, the former Executive Officer—to has supported “green” OA and we have been fully compliant head the APS. Kate’s major task has been to transition with the 2013 directive from the Office of Science and the management of APS to a CEO model with a Senior Technology Policy that the publications resulting from Management Team. She appointed Mark Doyle as Chief U.S. federally funded research be accessible to the public 12 Information Officer, James Taylor as Chief Operating months after publication. Since APS is a major international Officer, and Matthew Salter as the new Publisher. -
Graphene-Based Spintronic Components
Graphene-Based Spintronic Components Minggang Zeng,†,‡ Lei Shen,∗,† Haibin Su,¶,§ Miao Zhou,† Chun Zhang,†,∥ and Yuanping Feng∗,† Department of Physics, 2 Science Drive 3, National University of Singapore, Singapore 117542, Singapore, NanoCore, 5A Engineering Drive 4, National University of Singapore, Singapore 117576, Singapore, Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore, Institute of High Performance Computing, 1 Fusionopolis Way, Connexis 138632, Singapore, and Department of Chemistry, 3 Science Drive 3, National University of Singapore, Singapore 117543, Singapore E-mail: [email protected] ; [email protected] Abstract A major challenge of spintronics is in generating, controlling and detecting spin-polarized current. Manipulation of spin-polarized current, in particular, is difficult. We demonstrate here, based on calculated transport properties of graphene nanoribbons, that nearly ±100 % spin-polarized current can be generated in zigzag graphene nanoribbons (ZGNRs) and tuned by a source-drain voltage in the bipolar spin diode, in addition to magnetic configurations of the electrodes. This unusual transport property is attributed to the intrinsic transmission selection rule of the spin subbands near the Fermi level in ZGNRs. The simultaneous control of spin current by the bias voltage and the magnetic configurations of the electrodes provides an opportunity to implement a whole range of spintronics devices. We propose theoretical designs for a complete set of basic spintronic devices, including bipolar spin diode, transistor and logic gates, based on ZGNRs. Graphical TOC Introduction Spintronics, a new type of electronics that seeks to exploit the spin degree of freedom of an electron in addition to its charge, offers one of the most promising solutions for future high operating speed and energy-saving electronic devices.1 The major challenge of spintronics is the difficulty in generating, controlling and detecting spin-polarized current. -
Emerging Spintronics Phenomena and Applications
Emerging spintronics phenomena and applications Rahul Mishra and Hyunsoo Yang * Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore Development of future sensor, memory, and computing nanodevices based on novel physical concepts is one of the significant research endeavors in solid-state research. The field of spintronics is one such promising area of nanoelectronics which utilizes both the charge and spin of an electron for device operations. The advantage offered by spin systems is in their non-volatility and low- power functionality. This paper reviews emerging spintronic phenomena and the research advancements in diverse spin based applications. Spin devices and systems for logic, memories, emerging computing schemes, flexible electronics and terahertz emitters are discussed in this report. *[email protected] 1 I. Introduction Conventional sensor, memory, and computing electronics exploit the charge of an electron for their operations. However, along with charge, an electron is also characterized by its spin angular momentum or spin. It is the spin of an electron that manifests in the form of magnetism that we see in magnetic objects of the macro world. In the information technology age, magnetism has found industry applications in the massive digital data storage. The field of spintronics is centered on electron’s spin in conjunction with its charge. As we near the end of a several decade scaling of CMOS technologies due to fundamental physical limitations, utilizing the degree of spin freedom might be a natural choice for next generation technologies. An external energy source is not required for maintaining a particular spin- or magnetic-state in a spintronic device. -
Call for Papers | 2022 MRS Spring Meeting
Symposium CH01: Frontiers of In Situ Materials Characterization—From New Instrumentation and Method to Imaging Aided Materials Design Advancement in synchrotron X-ray techniques, microscopy and spectroscopy has extended the characterization capability to study the structure, phonon, spin, and electromagnetic field of materials with improved temporal and spatial resolution. This symposium will cover recent advances of in situ imaging techniques and highlight progress in materials design, synthesis, and engineering in catalysts and devices aided by insights gained from the state-of-the-art real-time materials characterization. This program will bring together works with an emphasis on developing and applying new methods in X-ray or electron diffraction, scanning probe microscopy, and other techniques to in situ studies of the dynamics in materials, such as the structural and chemical evolution of energy materials and catalysts, and the electronic structure of semiconductor and functional oxides. Additionally, this symposium will focus on works in designing, synthesizing new materials and optimizing materials properties by utilizing the insights on mechanisms of materials processes at different length or time scales revealed by in situ techniques. Emerging big data analysis approaches and method development presenting opportunities to aid materials design are welcomed. Discussion on experimental strategies, data analysis, and conceptual works showcasing how new in situ tools can probe exotic and critical processes in materials, such as charge and heat transfer, bonding, transport of molecule and ions, are encouraged. The symposium will identify new directions of in situ research, facilitate the application of new techniques to in situ liquid and gas phase microscopy and spectroscopy, and bridge mechanistic study with practical synthesis and engineering for materials with a broad range of applications. -
Member Services 2018
AMERICAN PHYSICAL SOCIETY Member Services 2018 JANUARY – DECEMBER 2018 GUIDELINES FOR PROFESSIONAL CONDUCT The Constitution of the American Physical Society states that the objective of the Society shall be the advancement and diffusion of the knowledge of physics. It is the purpose of this statement to advance that objective by presenting ethical guidelines for Society members. Each physicist is a citizen of the community of science. Each shares responsibility for the welfare of this community. Science is best advanced when there is mutual trust, based upon honest behavior, throughout the community. Acts of deception, or any other acts that deliberately compromise the advancement of science, are unacceptable. Honesty must be regarded as the cornerstone of ethics in science. Professional integrity in the formulation, conduct, and report- ing of physics activities reflects not only on the reputations of individual physicists and their organizations, but also on the image and credibility of the physics profession as perceived by scientific colleagues, government and the public. It is important that the tradition of ethical behavior be carefully maintained and transmitted with enthusiasm to future generations. The following are the minimal standards of ethical behavior relating to several critical aspects of the physics profession. Physicists have an individual and a collective responsibility to ensure that there is no compromise with these guidelines. RESEARCH RESULTS The results of research should be recorded and maintained in a form that allows analysis and review. Research data should be immediately available to scientific collaborators. Following publication, the data should be retained for a reasonable period in order to be available promptly and completely to responsible scientists. -
Simulating Twistronics in Acoustic Metamaterials
Simulating twistronics in acoustic metamaterials S. Minhal Gardezi,1 Harris Pirie,2 Stephen Carr,3 William Dorrell,2 and Jennifer E. Hoffman1, 2, ∗ 1School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA 2Department of Physics, Harvard University, Cambridge, MA, 02138, USA 3Brown Theoretical Physics Center and Department of Physics, Brown University, Providence, RI, 02912-1843, USA (Dated: March 24, 2021) Twisted van der Waals (vdW) heterostructures have recently emerged as a tunable platform for studying correlated electrons. However, these materials require laborious and expensive effort for both theoretical and experimental exploration. Here we numerically simulate twistronic behavior in acoustic metamaterials composed of interconnected air cavities in two stacked steel plates. Our classical analog of twisted bilayer graphene perfectly replicates the band structures of its quantum counterpart, including mode localization at a magic angle of 1:12◦. By tuning the thickness of the interlayer membrane, we reach a regime of strong interlayer tunneling where the acoustic magic angle appears as high as 6:01◦, equivalent to applying 130 GPa to twisted bilayer graphene. In this regime, the localized modes are over five times closer together than at 1:12◦, increasing the strength of any emergent non-linear acoustic couplings. INTRODUCTION cate, acoustic metamaterials have straightforward gov- erning equations, continuously tunable properties, fast 1 Van der Waals (vdW) heterostructures host a di- build times, and inexpensive characterization tools, mak- verse set of useful emergent properties that can be cus- ing them attractive testbeds to rapidly explore their tomized by varying the stacking configuration of sheets quantum counterparts. Sound waves in an acoustic meta- of two-dimensional (2D) materials, such as graphene, material can be reshaped to mimic the collective mo- other xenes, or transition-metal dichalcogenides [1{4]. -
![Arxiv:2004.03735V2 [Cond-Mat.Mes-Hall] 20 May 2020 1](https://docslib.b-cdn.net/cover/6235/arxiv-2004-03735v2-cond-mat-mes-hall-20-may-2020-1-766235.webp)
Arxiv:2004.03735V2 [Cond-Mat.Mes-Hall] 20 May 2020 1
Field Theory for Magnetic Monopoles in (Square, Artificial) Spin Ice Field Theory for Magnetic Monopoles in (Square, Artificial) Spin Ice Cristiano Nisoli1 Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA (Dated: 21 May 2020) Proceeding from the more general to the more concrete, we propose an equilibrium field theory describing spin ice systems in terms of topological charges and magnetic monopoles. We show that for a spin ice on a graph, the entropic interaction in a Gaussian approximation is the inverse of the graph Laplacian matrix, while the screening function for external charges is the inverse of the screened laplacian. We particularize the treatment to square and pyrochlore ice. For square ice we highlight the gauge-free duality between direct and perpendicular structure in terms of symmetry between charges and currents, typical of magnetic fragmentation in a two-dimensional setting. We derive structure factors, correlations, correlation lengths, and susceptibilities for spins, topological charges, and currents. We show that the divergence of the correlation length at low temperature is exponential and inversely proportional to the mean square charge. While in three dimension real and entropic interactions among monopoles are both 3D-Coulomb, in two dimension the former is a 3D-Coulomb and the latter 2D-Coulomb, or logarithmic, leading to weak singularities in correspondence of the pinch points and destroying charge screening. This suggests that the monopole plasma of square ice is a magnetic charge insulator. CONTENTS I. Introduction 2 II. Graph Spin Ice 3 A. Spins on a Graph3 1. Ice Manifold4 2. Coulomb Phases5 3. Energy5 B. -
Valleytronics: Opportunities, Challenges, and Paths Forward
REVIEW Valleytronics www.small-journal.com Valleytronics: Opportunities, Challenges, and Paths Forward Steven A. Vitale,* Daniel Nezich, Joseph O. Varghese, Philip Kim, Nuh Gedik, Pablo Jarillo-Herrero, Di Xiao, and Mordechai Rothschild The workshop gathered the leading A lack of inversion symmetry coupled with the presence of time-reversal researchers in the field to present their symmetry endows 2D transition metal dichalcogenides with individually latest work and to participate in honest and addressable valleys in momentum space at the K and K′ points in the first open discussion about the opportunities Brillouin zone. This valley addressability opens up the possibility of using the and challenges of developing applications of valleytronic technology. Three interactive momentum state of electrons, holes, or excitons as a completely new para- working sessions were held, which tackled digm in information processing. The opportunities and challenges associated difficult topics ranging from potential with manipulation of the valley degree of freedom for practical quantum and applications in information processing and classical information processing applications were analyzed during the 2017 optoelectronic devices to identifying the Workshop on Valleytronic Materials, Architectures, and Devices; this Review most important unresolved physics ques- presents the major findings of the workshop. tions. The primary product of the work- shop is this article that aims to inform the reader on potential benefits of valleytronic 1. Background devices, on the state-of-the-art in valleytronics research, and on the challenges to be overcome. We are hopeful this document The Valleytronics Materials, Architectures, and Devices Work- will also serve to focus future government-sponsored research shop, sponsored by the MIT Lincoln Laboratory Technology programs in fruitful directions. -
Relativistic Theory of Laser-Induced Magnetization Dynamics
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1558 Relativistic theory of laser-induced magnetization dynamics RITWIK MONDAL ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 ISBN 978-91-513-0070-2 UPPSALA urn:nbn:se:uu:diva-315247 2017 Dissertation presented at Uppsala University to be publicly examined in Polhemsalen, Lägerhyddsvägen 1, Uppsala, Friday, 27 October 2017 at 13:15 for the degree of Doctor of Philosophy. The examination will be conducted in English. Faculty examiner: Professor Paul- Antoine Hervieux (Université de Strasbourg). Abstract Mondal, R. 2017. Relativistic theory of laser-induced magnetization dynamics. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1558. 115 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-513-0070-2. Ultrafast dynamical processes in magnetic systems have become the subject of intense research during the last two decades, initiated by the pioneering discovery of femtosecond laser-induced demagnetization in nickel. In this thesis, we develop theory for fast and ultrafast magnetization dynamics. In particular, we build relativistic theory to explain the magnetization dynamics observed at short timescales in pump-probe magneto-optical experiments and compute from first-principles the coherent laser-induced magnetization. In the developed relativistic theory, we start from the fundamental Dirac-Kohn-Sham equation that includes all relativistic effects related to spin and orbital magnetism as well as the magnetic exchange interaction and any external electromagnetic field. As it describes both particle and antiparticle, a separation between them is sought because we focus on low-energy excitations within the particle system. Doing so, we derive the extended Pauli Hamiltonian that captures all relativistic contributions in first order; the most significant one is the full spin- orbit interaction (gauge invariant and Hermitian).