The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Rudolf Podgornik - One of the best experts on this subject based on the ideXlab platform.
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materials perspective on casimir and Van Der Waals interactions
Reviews of Modern Physics, 2016Co-Authors: Lilia M Woods, Rudolf Podgornik, Diego A. R. Dalvit, Alexandre Tkatchenko, Pablo Rodriguezlopez, Alejandro W RodriguezAbstract:Interactions induced by electromagnetic fluctuations, such as Van Der Waals and Casimir forces, are of universal nature present at any length scale between any types of systems with finite dimensions. Such interactions are important not only for the fundamental science of materials behavior, but also for the design and improvement of micro- and nano-structured devices. In the past decade, many new materials have become available, which has stimulated the need of unDerstanding their dispersive interactions. The field of Van Der Waals and Casimir forces has experienced an impetus in terms of developing novel theoretical and computational methods to provide new insights in related phenomena. The unDerstanding of such forces has far reaching consequences as it bridges concepts in materials, atomic and molecular physics, condensed matter physics, high energy physics, chemistry and biology. In this review, we summarize major breakthroughs and emphasize the common origin of Van Der Waals and Casimir interactions. We examine progress related to novel ab initio modeling approaches and their application in various systems, interactions in materials with Dirac-like spectra, force manipulations through nontrivial boundary conditions, and applications of Van Der Waals forces in organic and biological matter. The outlook of the review is to give the scientific community a materials perspective of Van Der Waals and Casimir phenomena and stimulate the development of experimental techniques and applications.
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Nonadditivity in Van Der Waals interactions within multilayers.
Journal of Chemical Physics, 2006Co-Authors: Rudolf Podgornik, Roger H. French, V. A. ParsegianAbstract:Working at the macroscopic continuum level, we investigate effective Van Der Waals interactions between two layers within a multilayer assembly. By comparing the pair interactions between two layers with effective pair interactions within an assembly we assess the significant consequences of nonadditivity of Van Der Waals interactions. This allows us to evaluate the best numerical estimate to date for the Hamaker coefficient of Van Der Waals interactions in lipid-water multilamellar systems.
Xiangfeng Duan - One of the best experts on this subject based on the ideXlab platform.
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Van Der Waals thin-film electronics
Nature Electronics, 2019Co-Authors: Zhaoyang Lin, Yu Huang, Xiangfeng DuanAbstract:The development of emerging applications based on large-area flexible and wearable devices requires solution-processable thin-film electronics. Organic semiconductors can be processed in solution, but typically suffer from relatively low performance and insufficient stability in ambient conditions. Inorganic nanostructures, however, can be processed in solution while retaining the excellent electronic performance and structural stability of crystalline inorganic materials. In particular, a range of two-dimensional inorganic nanosheets can be dispersed in various solvents as stable colloidal inks. These nanosheets can be assembled into continuous thin films in which neighbouring sheets interact via Van Der Waals forces with few interfacial trapping states. The resulting tiled nanosheets, which we term two-dimensional Van Der Waals thin films, offer significant potential in thin-film electronics. Here we explore the development of Van Der Waals thin films and their use in high-performance large-area electronics. We examine the formulation of the nanosheet inks and their scalable assembly into Van Der Waals thin films and devices. We also consiDer their application in large-area wearable electronics and the challenges that exist in delivering practical devices.This Perspective explores the development of solution-processable Van Der Waals thin films, examining their potential for application in large-area wearable electronics and the challenges that exist in delivering practical devices.
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Van Der Waals integration before and beyond two-dimensional materials
Nature, 2019Co-Authors: Yuan Liu, Yu Huang, Xiangfeng DuanAbstract:Material integration strategies, such as epitaxial growth, usually involve strong chemical bonds and are typically limited to materials with strict structure matching and processing compatibility. Van Der Waals integration, in which pre-fabricated building blocks are physically assembled together through weak Van Der Waals interactions, offers an alternative bond-free integration strategy without lattice and processing limitations, as exemplified by two-dimensional Van Der Waals heterostructures. Here we review the development, challenges and opportunities of this emerging approach, generalizing it for flexible integration of diverse material systems beyond two dimensions, and discuss its potential for creating artificial heterostructures or superlattices beyond the reach of existing materials.Recent adVances and future directions in the use of Van Der Waals integration beyond two-dimensional materials are reviewed.
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Van Der Waals heterostructures and devices
Nature Reviews Materials, 2016Co-Authors: Nathan O. Weiss, Xidong Duan, Hungchieh Cheng, Yu Huang, Xiangfeng DuanAbstract:With a dangling-bond-free surface, two dimensional layered materials (2DLMs) can enable the creation of diverse Van Der Waals heterostructures (vdWHs) without the conventional constraint of lattice matching or process compatibility. This Review discusses the recent adVances in exploring 2DLM vdWHs for future electronics and optoelectronics. Two-dimensional layered materials (2DLMs) have been a central focus of materials research since the discovery of graphene just over a decade ago. Each layer in 2DLMs consists of a covalently bonded, dangling-bond-free lattice and is weakly bound to neighbouring layers by Van Der Waals interactions. This makes it feasible to isolate, mix and match highly disparate atomic layers to create a wide range of Van Der Waals heterostructures (vdWHs) without the constraints of lattice matching and processing compatibility. Exploiting the novel properties in these vdWHs with diverse layering of metals, semiconductors or insulators, new designs of electronic devices emerge, including tunnelling transistors, barristors and flexible electronics, as well as optoelectronic devices, including photodetectors, photovoltaics and light-emitting devices with unprecedented characteristics or unique functionalities. We review the recent progress and challenges, and offer our perspective on the exploration of 2DLM-based vdWHs for future application in electronics and optoelectronics.
David C. Whitley - One of the best experts on this subject based on the ideXlab platform.
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Van Der Waals Surface Graphs and the Shape of Small Rings
Journal of Chemical Information and Computer Sciences, 1998Co-Authors: David C. WhitleyAbstract:A Van Der Waals surface graph is the graph defined on the Van Der Waals surface of a molecule by the intersections of the atomic Van Der Waals spheres. This is a discrete invariant of three-dimensional molecular shape. Two applications of these graphs to the study of small ring molecules are described: the basic shapes of rings up to orDer six are classified, and the results of a substructure search are analyzed, indicating how substructures with a specified three-dimensional shape may be identified.
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Van Der Waals surface graphs and molecular shape
Journal of Mathematical Chemistry, 1998Co-Authors: David C. WhitleyAbstract:A Van Der Waals surface graph is the graph defined on a Van Der Waals surface by the intersections of the atomic Van Der Waals spheres. A Van Der Waals shape graph has a vertex for each atom with a visible face on the Van Der Waals surface, and edges between vertices representing atoms with adjacent faces on the Van Der Waals surface. These are discrete invariants of three‐dimensional molecular shape. Some basic properties of Van Der Waals surface graphs are studied, including their relationship with the Voronoi diagram of the atom centres, and a class of molecular embeddings is identified for which the dual of the Van Der Waals surface graph coincides with the Van Der Waals shape graph.
Paulo Sergio L. De Souza - One of the best experts on this subject based on the ideXlab platform.
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Optimizing Van Der Waals calculi using Cell-lists and MPI
IEEE Congress on Evolutionary Computation, 2010Co-Authors: Daniel R. F. Bonetti, Alexandre C. B. Delbem, Gonzalo Travieso, Paulo Sergio L. De SouzaAbstract:Van Der Waals's energy models attraction and repulsion effects between pairs of atoms. This energy is used by ab initio methods to find the tertiary structure of a protein based only on its amino acid sequence and on a force field model. Several researches suggests Genetic Algorithms (GAs), are adequate for the development of ab initio approaches for protein structure prediction. A GA generates thousands of potential structures for a protein conformation, and evaluates the Van Der Waals' interaction in each generated structure. In practice, 99% of running time of the GA is used with the computation of Van Der Waals' energy. To compute the Van Der Waals energy for a given structure, we need to calculate effects of the interactions of all pairs of atoms in the structure. Using this cutoff, the complexity of the algorithm is O(n2) per conformation, where n is the number of atoms of the protein. For atoms separated by more than 8 Å the Van Der Waals effect is relatively weak. Thus, we apply a Cell-lists method to the Van Der Waals function reducing the complexity of algorithm to O(n). Furthermore, we applied parallel programming to the Cell-lists method using MPI, reducing significatively the running time. The combination of the Cell-lists and MPI techniques resulted in a speedup of 1000 for a protein with 147,900 atoms.
I V Grigorieva - One of the best experts on this subject based on the ideXlab platform.
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Van Der Waals heterostructures
Nature, 2013Co-Authors: A K Geim, I V GrigorievaAbstract:Fabrication techniques developed for graphene research allow the disassembly of many layered crystals (so-called Van Der Waals materials) into individual atomic planes and their reassembly into designer heterostructures, which reveal new properties and phenomena. Andre Geim and Irina Grigorieva offer a forward-looking review of the potential of layering two-dimensional materials into novel heterostructures held together by weak Van Der Waals interactions. Dozens of these one-atom- or one-molecule-thick crystals are known. Graphene has already been well studied but others, such as monolayers of hexagonal boron nitride, MoS2, WSe2, graphane, fluorographene, mica and silicene are attracting increasing interest. There are many other monolayers yet to be examined of course, and the possibility of combining graphene with other crystals adds even further options, offering exciting new opportunities for scientific exploration and technological innovation. Research on graphene and other two-dimensional atomic crystals is intense and is likely to remain one of the leading topics in condensed matter physics and materials science for many years. Looking beyond this field, isolated atomic planes can also be reassembled into designer heterostructures made layer by layer in a precisely chosen sequence. The first, already remarkably complex, such heterostructures (often referred to as ‘Van Der Waals’) have recently been fabricated and investigated, revealing unusual properties and new phenomena. Here we review this emerging research area and identify possible future directions. With steady improvement in fabrication techniques and using graphene’s springboard, Van Der Waals heterostructures should develop into a large field of their own.
