Multiscale theory of memristive materials systems

忆阻材料系统的多尺度理论

• 批准号: 1207241
• 负责人: Sokrates Pantelides
• 金额: $ 31.7万
• 依托单位: Vanderbilt University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1207241&HistoricalAwards=false
• 关键词: Multiscale; theory; memristive; materials; systems

TECHNICAL SUMMARYThis award supports computational and theoretical research and education on memristive materials. Memristive materials exhibit intrinsic nonlinear conduction behavior due to the coupling between electronic and ionic conduction, the latter being mediated by defects, such as vacancies and interstitials. A subclass of materials, usually referred to as resistive-switching materials, can be switched between a high-resistance state and a low-resistance state and may be ideal for constructing resistive random access memory. More generally, memristive materials feature a hysteresis loop in their I-V characteristics. Besides memory applications, they can lead to new analog applications and even bio-inspired neuromorphic circuits, both of which utilize a gradual 'switch' in the I-V characteristics. However, the lack of an accurate description of defect dynamics and its interplay with electronic conduction has become a major obstacle for realizing the potential of the materials. The PI will focus on revealing the underlying physics and chemistry in memristive phenomena.The PI will establish a multiscale theoretical framework based on first-principles quantum-mechanical calculations using realistic atomic models and apply it to investigate the memristive switching in various materials systems. The atomic-scale investigation will include first-principles calculations of defects, their interactions, and pertinent electron energy levels. The effects of the defects on the conductivity will be probed using first-principles transport codes. Defect energetics will be incorporated in a kinetic Monte-Carlo model to obtain realistic I-V behavior of the materials. Since the focus is on the microscopic mechanisms of the memristive switching, the proposed research will identify the fundamental properties of the materials that affect their switching performance. The proposed research will also construct physics-based state equations that will be the foundation of device and circuit design. Interactions with experimental and engineering groups at universities and industry will be pursued. Extensive education outreach will be made to high schools and the broader society.NON-TECHNICAL SUMMARYThis award supports computational and theoretical research and education on memristive materials. Memristive materials conduct electricity in an interesting way that can lead to devices for memory applications, be a basis for new types of analog circuits, and even introduce neuromorphic computers that mimic the biological brain functions. In many materials, electric current flowing through the material is linearly related to the voltage across the material. In memristive materials, the relation between current and voltage is nonlinear. While conduction of electrons through metals originates from the flow of electrons alone, the non-linearity in memristive materials originates from the coupled conduction by electrons and conduction by ions in the materials, the latter being mediated by defects in the regular arrangement of atoms in the materials, such as missing atoms or vacancies. The PI aims to develop a fundamental understanding of the way electric current flows through these materials by coupled electron and ion motion and the mechanisms that underlie the memristive behavior. The PI aims to conduct theoretical and computational investigations in order to illuminate the conduction process at the microscopic level, identify the origin of the memristive behavior, and establish correlations between atomic-scale properties of materials and their implications for conductive phenomena. Broad interactions with experimentalists and engineers will be a part of the program. Extensive education outreach will make advances accessible to high schools and the community.

该奖项支持忆阻材料的计算和理论研究和教育。忆阻材料由于电子传导和离子传导之间的耦合而表现出固有的非线性传导行为，后者由诸如空位和介导。材料的子类，通常被称为连续切换材料，可以在高电阻状态和低电阻状态之间切换，并且可以是构造电阻式随机存取存储器的理想材料。更一般地，忆阻材料在其I-V特性中以磁滞回线为特征。除了存储器应用之外，它们还可以导致新的模拟应用，甚至是生物启发的神经形态电路，这两者都利用了I-V特性中的逐渐“切换”。 然而，缺乏对缺陷动力学及其与电子传导的相互作用的准确描述已经成为实现材料潜力的主要障碍。该项目将致力于揭示忆阻现象背后的物理和化学原理，并将基于第一性原理量子力学计算，利用真实原子模型建立多尺度理论框架，并将其应用于研究各种材料系统中的忆阻开关。原子尺度的研究将包括缺陷的第一原理计算，它们的相互作用，以及相关的电子能级。将使用第一性原理传输代码探测缺陷对电导率的影响。缺陷能量学将被纳入动力学蒙特-卡罗模型，以获得现实的I-V行为的材料。由于重点是忆阻开关的微观机制，因此拟议的研究将确定影响其开关性能的材料的基本特性。拟议的研究还将构建基于物理的状态方程，这将是器件和电路设计的基础。将继续与大学和工业界的实验和工程小组进行互动。将广泛的教育推广到高中和更广泛的社会。非技术总结这个奖项支持计算和理论研究和教育的忆阻材料。忆阻材料以一种有趣的方式导电，可以导致用于存储器应用的设备，成为新型模拟电路的基础，甚至引入模仿生物大脑功能的神经形态计算机。 在许多材料中，流过材料的电流与材料两端的电压线性相关。在忆阻材料中，电流和电压之间的关系是非线性的。虽然电子通过金属的传导仅源于电子的流动，但忆阻材料中的非线性源于材料中的电子传导和离子传导的耦合，后者由材料中原子的规则布置中的缺陷（诸如缺失原子或空位）介导。PI旨在通过耦合电子和离子运动以及记忆行为的基础机制，对电流流过这些材料的方式进行基本理解。PI旨在进行理论和计算研究，以阐明微观层面的传导过程，确定忆阻行为的起源，并建立材料的原子尺度性质及其对传导现象的影响之间的相关性。与实验学家和工程师的广泛互动将是该计划的一部分。广泛的教育推广将使高中和社区能够获得进步。