Download or read book Accurate Quantum Mechanical Modeling of Defects in Two dimensional and Three dimensional Materials written by Elham Khorasani and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Layered materials beyond graphite such as hexagonal boron nitride (hBN) and transition metal dichalcogenides (TMDCs) like molybdenum disulfide (MoS2) are presently under intense study, and most applications require knowledge about their defects. In this work, first, density functional theory (DFT) has been employed to study the defects properties in hBN. According to earlier studies, the screened hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE), with parameters tuned to reproduce the relative position of the band edges and to satisfy the generalized Koopmans' theorem (gKT) , is capable of providing defect properties very accurately in traditional bulk semiconductors. This success is concluded to be connected to the proper description of electronic screening. I investigate whether such a functional can be optimized for layer compund such as hBN. I find that while the optimization is possible for bulk hBN, the optimized parameters can only be met approximately for the atomatically thin monolayer (ML) hBN. So, generally, the quantitative accuracy of defect calculations in 2D layers is limited. Using an optimized hybrid functional in bulk hBN, which reproduces the gap and satisfies the generalized Koopmans condition, an Ni configuration is found to be lower in energy than the ones reported so far. The (0/-) charge transition level is also much deeper, so Ni acts as a very efficient compensating center in n-type samples. Its calculated photoluminescence (PL) at 3.0 eV agrees well with the position of an N-sensitive band measured at 3.1 eV. Hyperfine interactions have been also performed to investigate the three boron electron (TBC) electron paramagnetic resonance (EPR) center in bulk hBN. I find that the carbon substitutional on the nitrogen site (CN) is the source of carbon-associated TBC in hBN in agreement with a previous study. I also show that the nitrogen vacancy (VN) cannot be the origin of the electron-associated produced TBC in hBN and in thermal equilibrium it cannot exist in ntype samples. Similarly, defects in van der Waals layered MoS2, play an important role. I present our first principle investigation of a water splitting for a defective monolayer molybdenum disulfide (ML MoS2). Defects such as molybdenum vacancy (VMo) and a vacancy complex of Mo and three S (VMoS3 ) in two configurations are considered. The complex defect VMoS3, where a pair of sulfur vacancies is placed on the top plane and the third vacancy on the bottom plane, is found to be sufficiently active to split the water molecule into OH and H. The water dissociation not occur for the complex defect VMoS3 if all sulfur vacancies are located at the surface. The presented results are critical for designing chemical sensing and hydrogen generation devices from MoS2.
Download or read book Defects in Two Dimensional Materials written by Rafik Addou and published by Elsevier. This book was released on 2022-02-14 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defects in Two-Dimensional Materials addresses the fundamental physics and chemistry of defects in 2D materials and their effects on physical, electrical and optical properties. The book explores 2D materials such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMD). This knowledge will enable scientists and engineers to tune 2D materials properties to meet specific application requirements. The book reviews the techniques to characterize 2D material defects and compares the defects present in the various 2D materials (e.g. graphene, h-BN, TMDs, phosphorene, silicene, etc.). As two-dimensional materials research and development is a fast-growing field that could lead to many industrial applications, the primary objective of this book is to review, discuss and present opportunities in controlling defects in these materials to improve device performance in general or use the defects in a controlled way for novel applications. Presents the theory, physics and chemistry of 2D materials Catalogues defects of 2D materials and their impacts on materials properties and performance Reviews methods to characterize, control and engineer defects in 2D materials
Download or read book Synthesis Modelling and Characterization of 2D Materials and their Heterostructures written by Eui-Hyeok Yang and published by Elsevier. This book was released on 2020-06-19 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesis, Modelling and Characterization of 2D Materials and Their Heterostructures provides a detailed discussion on the multiscale computational approach surrounding atomic, molecular and atomic-informed continuum models. In addition to a detailed theoretical description, this book provides example problems, sample code/script, and a discussion on how theoretical analysis provides insight into optimal experimental design. Furthermore, the book addresses the growth mechanism of these 2D materials, the formation of defects, and different lattice mismatch and interlayer interactions. Sections cover direct band gap, Raman scattering, extraordinary strong light matter interaction, layer dependent photoluminescence, and other physical properties. Explains multiscale computational techniques, from atomic to continuum scale, covering different time and length scales Provides fundamental theoretical insights, example problems, sample code and exercise problems Outlines major characterization and synthesis methods for different types of 2D materials
Download or read book NBS Special Publication written by and published by . This book was released on 1978 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interacting Electrons in Reduced Dimensions written by Dionys Baeriswyl and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: As its name suggests, the 1988 workshop on "Interacting Electrons in Reduced Dimen the wide variety of physical effects that are associated with (possibly sions" focused on strongly) correlated electrons interacting in quasi-one- and quasi-two-dimensional mate rials. Among the phenomena discussed were superconductivity, magnetic ordering, the metal-insulator transition, localization, the fractional Quantum Hall effect (QHE), Peierls and spin-Peierls transitions, conductance fluctuations and sliding charge-density (CDW) and spin-density (SDW) waves. That these effects appear most pronounced in systems of reduced dimensionality was amply demonstrated at the meeting. Indeed, when concrete illustrations were presented, they typically involved chain-like materials such as conjugated polymers, inorganic CDW systems and organie conductors, or layered materials such as high-temperature copper-oxide superconductors, certain of the organic superconductors, and the QHE samples, or devices where the electrons are confined to a restricted region of sample, e. g. , the depletion layer of a MOSFET. To enable this broad subject to be covered in thirty-five lectures (and ab out half as many posters), the workshop was deliberately focused on theoretical models for these phenomena and on methods for describing as faithfully as possible the "true" behav ior of these models. This latter emphasis was especially important, since the inherently many-body nature of problems involving interacting electrons renders conventional effec tive single-particle/mean-field methods (e. g. , Hartree-Fock or the local-density approxi mation in density-functional theory) highly suspect. Again, this is particularly true in reduced dimensions, where strong quantum fluctuations can invalidate mean-field results.
Download or read book Machine Learning Meets Quantum Physics written by Kristof T. Schütt and published by Springer Nature. This book was released on 2020-06-03 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designing molecules and materials with desired properties is an important prerequisite for advancing technology in our modern societies. This requires both the ability to calculate accurate microscopic properties, such as energies, forces and electrostatic multipoles of specific configurations, as well as efficient sampling of potential energy surfaces to obtain corresponding macroscopic properties. Tools that can provide this are accurate first-principles calculations rooted in quantum mechanics, and statistical mechanics, respectively. Unfortunately, they come at a high computational cost that prohibits calculations for large systems and long time-scales, thus presenting a severe bottleneck both for searching the vast chemical compound space and the stupendously many dynamical configurations that a molecule can assume. To overcome this challenge, recently there have been increased efforts to accelerate quantum simulations with machine learning (ML). This emerging interdisciplinary community encompasses chemists, material scientists, physicists, mathematicians and computer scientists, joining forces to contribute to the exciting hot topic of progressing machine learning and AI for molecules and materials. The book that has emerged from a series of workshops provides a snapshot of this rapidly developing field. It contains tutorial material explaining the relevant foundations needed in chemistry, physics as well as machine learning to give an easy starting point for interested readers. In addition, a number of research papers defining the current state-of-the-art are included. The book has five parts (Fundamentals, Incorporating Prior Knowledge, Deep Learning of Atomistic Representations, Atomistic Simulations and Discovery and Design), each prefaced by editorial commentary that puts the respective parts into a broader scientific context.
Download or read book Theoretical Aspects of Heterogeneous Catalysis written by M.A. Nascimento and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterogeneous catalysis is a fascinating and complex subject of utmost importance in the present day. Its immense technological and economical importance and the inherent complexity of the catalytic phenomena have stimulated theoretical and experimental studies by a broad spectrum of scientists, including chemists, physicists, chemical engineers, and material scientists. Computational and theoretical techniques are now having a major impact in this field. This book aims to illustrate and discuss the subject of heterogeneous catalysis and to show the current capabilities of the theoretical and computational methods for studying the various steps (diffusion, adsorption, chemical reaction) of heterogeneous catalytic process involving zeolites, metal oxides, and transition metal surfaces. The book covers: the use of techniques of computational chemistry to simulate zeolites, metallic and bimetallic surfaces, and oxide-supported metals; the impact of simulation methods on the understanding of the diffusion and adsorption of molecules and cations within the pores of zeolites, and also on the adsorption of molecules on metal and metal-oxide surfaces; and the applications of quantum-mechanical methods to the study of the reaction mechanism and pathways of the adsorbed molecules. This book is recommended primarily to scientists and graduate students conducting research in the fields of heterogeneous catalysis and surface science. It will also be valuable to advanced undergraduate students wishing to become acquainted with the latest developments in these exciting fields of research, and to experimentalists seeking theoretical support for interpreting their results.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Approaches to Energy Materials written by Richard Catlow and published by John Wiley & Sons. This book was released on 2013-04-03 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of materials for clean and efficient energy generation and storage is one of the most rapidly developing, multi-disciplinary areas of contemporary science, driven primarily by concerns over global warming, diminishing fossil-fuel reserves, the need for energy security, and increasing consumer demand for portable electronics. Computational methods are now an integral and indispensable part of the materials characterisation and development process. Computational Approaches to Energy Materials presents a detailed survey of current computational techniques for the development and optimization of energy materials, outlining their strengths, limitations, and future applications. The review of techniques includes current methodologies based on electronic structure, interatomic potential and hybrid methods. The methodological components are integrated into a comprehensive survey of applications, addressing the major themes in energy research. Topics covered include: • Introduction to computational methods and approaches • Modelling materials for energy generation applications: solar energy and nuclear energy • Modelling materials for storage applications: batteries and hydrogen • Modelling materials for energy conversion applications: fuel cells, heterogeneous catalysis and solid-state lighting • Nanostructures for energy applications This full colour text is an accessible introduction for newcomers to the field, and a valuable reference source for experienced researchers working on computational techniques and their application to energy materials.
Download or read book Computer Simulation of Materials at Atomic Level written by P鈋ter·De鈇k and published by John Wiley & Sons. This book was released on 2000 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt: Peter Dea, Thomas Frauenheim, Mark R. Pederson (eds.) Computer Simulation of Materials at Atomic Level Combining theory and applications, this book deals with the modelling of materials properties and phenomena at atomic level. The first part provides an overview of the state-of-the-art of computational solid state physics. Emphasis is given on the understanding of approximations and their consequences regarding the accuracy of the results. This part of the book also deals as a guide to find the best method for a given purpose. The second part offers a potpourri of interesting topical applications, showing what can be achieved by computational modelling. Here the possibilities and the limits of the methods are stressed. A CD-ROM supplies various demo programmes of applications.
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ECAI 2020 written by G. De Giacomo and published by IOS Press. This book was released on 2020-09-11 with total page 3122 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the proceedings of the 24th European Conference on Artificial Intelligence (ECAI 2020), held in Santiago de Compostela, Spain, from 29 August to 8 September 2020. The conference was postponed from June, and much of it conducted online due to the COVID-19 restrictions. The conference is one of the principal occasions for researchers and practitioners of AI to meet and discuss the latest trends and challenges in all fields of AI and to demonstrate innovative applications and uses of advanced AI technology. The book also includes the proceedings of the 10th Conference on Prestigious Applications of Artificial Intelligence (PAIS 2020) held at the same time. A record number of more than 1,700 submissions was received for ECAI 2020, of which 1,443 were reviewed. Of these, 361 full-papers and 36 highlight papers were accepted (an acceptance rate of 25% for full-papers and 45% for highlight papers). The book is divided into three sections: ECAI full papers; ECAI highlight papers; and PAIS papers. The topics of these papers cover all aspects of AI, including Agent-based and Multi-agent Systems; Computational Intelligence; Constraints and Satisfiability; Games and Virtual Environments; Heuristic Search; Human Aspects in AI; Information Retrieval and Filtering; Knowledge Representation and Reasoning; Machine Learning; Multidisciplinary Topics and Applications; Natural Language Processing; Planning and Scheduling; Robotics; Safe, Explainable, and Trustworthy AI; Semantic Technologies; Uncertainty in AI; and Vision. The book will be of interest to all those whose work involves the use of AI technology.
Download or read book Publications of the National Bureau of Standards Catalog written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Digital Visualization and Quantification of Material Defects written by Chao Zhu and published by . This book was released on 2009 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 2D Materials written by Phaedon Avouris and published by Cambridge University Press. This book was released on 2017-06-29 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn about the most recent advances in 2D materials with this comprehensive and accessible text. Providing all the necessary materials science and physics background, leading experts discuss the fundamental properties of a wide range of 2D materials, and their potential applications in electronic, optoelectronic and photonic devices. Several important classes of materials are covered, from more established ones such as graphene, hexagonal boron nitride, and transition metal dichalcogenides, to new and emerging materials such as black phosphorus, silicene, and germanene. Readers will gain an in-depth understanding of the electronic structure and optical, thermal, mechanical, vibrational, spin and plasmonic properties of each material, as well as the different techniques that can be used for their synthesis. Presenting a unified perspective on 2D materials, this is an excellent resource for graduate students, researchers and practitioners working in nanotechnology, nanoelectronics, nanophotonics, condensed matter physics, and chemistry.
Download or read book Publications of the National Institute of Standards and Technology 1988 Catalog written by Rebecca J. Pardee and published by . This book was released on 1989 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 50 years of Statistical Physics in Mexico Development State of the Art and Perspectives written by Ramon Castañeda-Priego and published by Frontiers Media SA. This book was released on 2021-09-13 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt:
