NSF/DMR-BSF: Stochastic Electronic Structure Approaches Applied to Study Low-Dimensional Black-Phosphorene Systems

NSF/DMR-BSF：应用于研究低维黑磷烯系统的随机电子结构方法

• 批准号: 1611382
• 负责人: Daniel Neuhauser
• 金额: $ 51.16万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1611382&HistoricalAwards=false
• 关键词: NSF; DMR; BSF; Stochastic; Electronic

NONTECHNICAL SUMMARYThe National Science Foundation and the United States -- Israel Binational Science Foundation (BSF) jointly support this collaboration between a US-based researcher and an Israel-based researcher. The NSF Divisions of Materials Research and Chemistry fund this award jointly. The award supports computational research and education on the mechanical and electronic properties of black phosphorene. Black phosphorene is a material composed of elemental phosphorous that has been discovered and synthesized only recently. It is very similar to graphene, it forms a two-dimensional sheet, but it offers a significant advantage in that it behaves as a semiconductor: it exhibits a sizeable energy gap while supporting at the same time high-mobility charge carriers. In addition, it turns out that the electronic properties of black phosphorene can be readily tuned by applying mechanical stress and other methods. Therefore, just as silicon emerged as an ideal material for three-dimensional electronics, black phosphorene seems to emerge as the ideal infrastructure material for two-dimensional electronics technology. The principal goal of this project is to study, understand, and eventually predict the properties of black phosphorene and its derivatives using theoretical and computational methods. Because of the way two-dimensional black phosphorene responds to mechanical stresses and to chemical perturbations, studying its properties using conventional computational methods is a highly challenging task, requiring the simulation of exceedingly large systems. Therefore, the first challenge the project will need to overcome is to build a computational tool that tackles large electronic systems containing thousands of atoms, and apply it to the study of black phosphorene. This challenge can be met by using methodologies developed by the PIs that can generally be described as stochastic computational techniques. These approaches are akin to statistical methods used in polling, and make it possible to accurately simulate material properties for much larger systems than is possible with traditional, non-stochastic approaches. Once the tools are developed, the PIs will use them to study realistic two-dimensional black-phosphorene sheets, providing a theoretical framework for fundamental understanding and for guiding future experiments on this material.The theoretical tools developed and used in this project will be made available to the community, with an aim to increase access to the developed methodology. The educational component of the project emphasizes the use of computational tools relevant for the research for the training and education of graduate students and postdoctoral fellows. Undergraduate and high school students will be involved in the research, especially in the running of large-scale simulations. All will benefit from close interactions with the Israeli collaborators.TECHNICAL SUMMARYThe National Science Foundation and the United States -- Israel Binational Science Foundation (BSF) jointly support this collaboration between a US-based researcher and an Israel-based researcher. The NSF Divisions of Materials Research and Chemistry fund this award jointly. The award supports computational research and education on the mechanical and electronic properties of black phosphorene. Traditional large-scale simulations of these properties are prohibitively expensive either for accurate density functional theory with exact exchange (DFT), or for highly accurate electronic structure methods based on Green's function (GW). This project will explore hitherto inaccessible regimes using the stochastic formulations of traditional DFT and GW. The stochastic formulations replace some, or all of the multitude of summations over orbitals inherent in electronics structure methods with a stochastic sampling of combinations of these orbitals. The stochastic approaches are designed to calculate from first principles the atomic and electronic structure of systems containing 10,000 atoms or more. Sizes of that magnitude are necessary for establishing realistic environments, which enable the study of anisotropic properties. Such capability allows the construction of a theoretical framework for fundamental understanding of black phosphorene, which in turn will help in guiding experiments and synthetic efforts by pointing out possible directions to achieve desired properties. The unique ability to accurately simulate large black-phosphorene systems allows the exploration of electronic structure under a variety of experimental conditions, which include temperature, strain, and optical excitation. Using a combination of stochastic DFT and Langevin dynamics, the structure and phonon dispersion curves of large, layered black-phosphorene nanoribbons and nanotubes will be investigated, with and without mechanical stress. The structure of defects and adsorbates on the surface and perimeters will be studied as well.The theoretical tools developed and used in this project will be made available to the community, with an aim to increase access to the developed methodology. The educational component of the project emphasizes the use of computational tools relevant for the research for the training and education of graduate students and postdoctoral fellows. Undergraduate and high school students will be involved in the research, especially in the running of large-scale simulations. All will benefit from close interactions with the Israeli collaborators.

非技术总结国家科学基金会和美国 - 以色列双原则科学基金会（BSF）共同支持美国研究人员与以色列研究人员之间的这一合作。材料研究和化学基金的NSF部门共同颁发。该奖项支持有关黑磷烯的机械和电子特性的计算研究和教育。黑磷烯是一种由元素磷的材料，直到最近才发现和合成。它与石墨烯非常相似，形成二维纸，但是它具有重要的优势，因为它表现为半导体：它具有相当大的能量差距，同时在同时支撑高弹性载体载体。此外，事实证明，黑磷烯的电子特性可以通过应用机械应力和其他方法来调节。因此，就像硅成为三维电子产品的理想材料一样，黑磷烯似乎是二维电子技术的理想基础设施材料。该项目的主要目标是使用理论和计算方法研究，理解并最终预测黑磷及其衍生物的特性。由于二维黑磷烯对机械应力和化学扰动的反应方式，因此使用常规计算方法研究其性质是一项高度挑战的任务，需要模拟非常大的系统。因此，该项目将需要克服的第一个挑战是构建一种计算工具，该工具可以应对包含数千原子的大型电子系统，并将其应用于黑磷烯的研究。可以通过使用PIS开发的方法来应对这一挑战，而PI通常可以将其描述为随机计算技术。这些方法类似于在轮询中使用的统计方法，并且可以准确地模拟与传统非传统方法相比，更大的系统的材料特性。一旦开发了工具，PIS将使用它们来研究现实的二维黑磷酸片，为基本理解和指导对此材料的未来实验提供了理论框架。该项目开发和使用的理论工具将提供给社区，以增加对开发方法的访问。该项目的教育组成部分强调使用与研究和教育研究生和博士后研究员的研究和教育相关的计算工具。本科生和高中生将参与研究，尤其是进行大规模模拟的运行。全部将受益于与以色列合作者的紧密互动。技术总结国家科学基金会和美国 - 以色列双原则科学基金会（BSF）共同支持美国研究人员与以色列研究人员之间的这一合作。材料研究和化学基金的NSF部门共同颁发。该奖项支持有关黑磷烯的机械和电子特性的计算研究和教育。传统的对这些性质的大规模模拟对于具有精确交换（DFT）的准确密度功能理论或基于Green功能（GW）的高度准确的电子结构方法而过高的昂贵。该项目将使用传统DFT和GW的随机配方来探索迄今无法访问的政权。随机配方用这些轨道组合的随机抽样取代了电子结构方法固有的轨道上的一些或所有众多求和。随机方法旨在根据第一个原理计算出包含10,000个原子或更多原子的系统的原子和电子结构。大小的尺寸对于建立现实的环境是必需的，这可以研究各向异性特性。这种能力允许建立一个理论框架，以基本理解黑磷烯，这反过来又可以通过指出可能的方向来实现所需特性来指导实验和综合工作。准确模拟大型黑磷酸系统的独特能力允许在各种实验条件下探索电子结构，包括温度，应变和光激发。使用随机DFT和Langevin动力学的组合，将研究有或没有机械应力的大型黑磷酸纳米骨和纳米管的结构和声子分散曲线。还将研究表面和周边的缺陷和吸附物的结构。该项目中开发和使用的理论工具将提供给社区，以增加对开发方法的访问。该项目的教育组成部分强调使用与研究和教育研究生和博士后研究员的研究和教育相关的计算工具。本科生和高中生将参与研究，尤其是进行大规模模拟的运行。与以色列合作者的紧密互动将受益。